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| <div class="subTitle">org.apache.kafka.streams.kstream</div> |
| <h2 title="Interface KStream" class="title">Interface KStream<K,V></h2> |
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| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>K</code> - Type of keys</dd> |
| <dd><code>V</code> - Type of values</dd> |
| </dl> |
| <hr> |
| <br> |
| <pre>public interface <span class="typeNameLabel">KStream<K,V></span></pre> |
| <div class="block"><code>KStream</code> is an abstraction of a <i>record stream</i> of <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pairs, i.e., each record is an |
| independent entity/event in the real world. |
| For example a user X might buy two items I1 and I2, and thus there might be two records <code><K:I1>, <K:I2></code> |
| in the stream. |
| <p> |
| A <code>KStream</code> is either <a href="../../../../../org/apache/kafka/streams/StreamsBuilder.html#stream-java.lang.String-"><code>defined from one or multiple Kafka topics</code></a> that |
| are consumed message by message or the result of a <code>KStream</code> transformation. |
| A <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> can also be <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html#toStream--"><code>converted</code></a> into a <code>KStream</code>. |
| <p> |
| A <code>KStream</code> can be transformed record by record, joined with another <code>KStream</code>, <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a>, or can be aggregated into a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| Kafka Streams DSL can be mixed-and-matched with Processor API (PAPI) (c.f. <a href="../../../../../org/apache/kafka/streams/Topology.html" title="class in org.apache.kafka.streams"><code>Topology</code></a>) via |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(...)</code></a>, and |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(...)</code></a>.</div> |
| <dl> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/StreamsBuilder.html#stream-java.lang.String-"><code>StreamsBuilder.stream(String)</code></a></dd> |
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| <h3>Method Summary</h3> |
| <table class="memberSummary" border="0" cellpadding="3" cellspacing="0" summary="Method Summary table, listing methods, and an explanation"> |
| <caption><span id="t0" class="activeTableTab"><span>All Methods</span><span class="tabEnd"> </span></span><span id="t2" class="tableTab"><span><a href="javascript:show(2);">Instance Methods</a></span><span class="tabEnd"> </span></span><span id="t3" class="tableTab"><span><a href="javascript:show(4);">Abstract Methods</a></span><span class="tabEnd"> </span></span><span id="t6" class="tableTab"><span><a href="javascript:show(32);">Deprecated Methods</a></span><span class="tabEnd"> </span></span></caption> |
| <tr> |
| <th class="colFirst" scope="col">Modifier and Type</th> |
| <th class="colLast" scope="col">Method and Description</th> |
| </tr> |
| <tr id="i0" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>>[]</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#branch-org.apache.kafka.streams.kstream.Named-org.apache.kafka.streams.kstream.Predicate...-">branch</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>>... predicates)</code> |
| <div class="block">Creates an array of <code>KStream</code> from this stream by branching the records in the original stream based on |
| the supplied predicates.</div> |
| </td> |
| </tr> |
| <tr id="i1" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>>[]</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#branch-org.apache.kafka.streams.kstream.Predicate...-">branch</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>>... predicates)</code> |
| <div class="block">Creates an array of <code>KStream</code> from this stream by branching the records in the original stream based on |
| the supplied predicates.</div> |
| </td> |
| </tr> |
| <tr id="i2" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#filter-org.apache.kafka.streams.kstream.Predicate-">filter</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> predicate)</code> |
| <div class="block">Create a new <code>KStream</code> that consists of all records of this stream which satisfy the given predicate.</div> |
| </td> |
| </tr> |
| <tr id="i3" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#filter-org.apache.kafka.streams.kstream.Predicate-org.apache.kafka.streams.kstream.Named-">filter</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> predicate, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Create a new <code>KStream</code> that consists of all records of this stream which satisfy the given predicate.</div> |
| </td> |
| </tr> |
| <tr id="i4" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#filterNot-org.apache.kafka.streams.kstream.Predicate-">filterNot</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> predicate)</code> |
| <div class="block">Create a new <code>KStream</code> that consists all records of this stream which do <em>not</em> satisfy the given |
| predicate.</div> |
| </td> |
| </tr> |
| <tr id="i5" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#filterNot-org.apache.kafka.streams.kstream.Predicate-org.apache.kafka.streams.kstream.Named-">filterNot</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> predicate, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Create a new <code>KStream</code> that consists all records of this stream which do <em>not</em> satisfy the given |
| predicate.</div> |
| </td> |
| </tr> |
| <tr id="i6" class="altColor"> |
| <td class="colFirst"><code><KR,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-">flatMap</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><? extends KR,? extends VR>>> mapper)</code> |
| <div class="block">Transform each record of the input stream into zero or more records in the output stream (both key and value type |
| can be altered arbitrarily).</div> |
| </td> |
| </tr> |
| <tr id="i7" class="rowColor"> |
| <td class="colFirst"><code><KR,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Named-">flatMap</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><? extends KR,? extends VR>>> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Transform each record of the input stream into zero or more records in the output stream (both key and value type |
| can be altered arbitrarily).</div> |
| </td> |
| </tr> |
| <tr id="i8" class="altColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-">flatMapValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream">ValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends VR>> mapper)</code> |
| <div class="block">Create a new <code>KStream</code> by transforming the value of each record in this stream into zero or more values |
| with the same key in the new stream.</div> |
| </td> |
| </tr> |
| <tr id="i9" class="rowColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-org.apache.kafka.streams.kstream.Named-">flatMapValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream">ValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends VR>> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Create a new <code>KStream</code> by transforming the value of each record in this stream into zero or more values |
| with the same key in the new stream.</div> |
| </td> |
| </tr> |
| <tr id="i10" class="altColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-">flatMapValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream">ValueMapperWithKey</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends VR>> mapper)</code> |
| <div class="block">Create a new <code>KStream</code> by transforming the value of each record in this stream into zero or more values |
| with the same key in the new stream.</div> |
| </td> |
| </tr> |
| <tr id="i11" class="rowColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-org.apache.kafka.streams.kstream.Named-">flatMapValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream">ValueMapperWithKey</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends VR>> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Create a new <code>KStream</code> by transforming the value of each record in this stream into zero or more values |
| with the same key in the new stream.</div> |
| </td> |
| </tr> |
| <tr id="i12" class="altColor"> |
| <td class="colFirst"><code><K1,V1> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><K1,V1></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-">flatTransform</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">TransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><<a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><K1,V1>>> transformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform each record of the input stream into zero or more records in the output stream (both key and value type |
| can be altered arbitrarily).</div> |
| </td> |
| </tr> |
| <tr id="i13" class="rowColor"> |
| <td class="colFirst"><code><K1,V1> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><K1,V1></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-">flatTransform</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">TransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><<a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><K1,V1>>> transformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform each record of the input stream into zero or more records in the output stream (both key and value type |
| can be altered arbitrarily).</div> |
| </td> |
| </tr> |
| <tr id="i14" class="altColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-">flatTransformValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><VR>> valueTransformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform the value of each input record into zero or more new values (with possibly a new |
| type) and emit for each new value a record with the same key of the input record and the value.</div> |
| </td> |
| </tr> |
| <tr id="i15" class="rowColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-">flatTransformValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><VR>> valueTransformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform the value of each input record into zero or more new values (with possibly a new |
| type) and emit for each new value a record with the same key of the input record and the value.</div> |
| </td> |
| </tr> |
| <tr id="i16" class="altColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-">flatTransformValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerWithKeySupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><VR>> valueTransformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform the value of each input record into zero or more new values (with possibly a new |
| type) and emit for each new value a record with the same key of the input record and the value.</div> |
| </td> |
| </tr> |
| <tr id="i17" class="rowColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-">flatTransformValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerWithKeySupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><VR>> valueTransformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform the value of each input record into zero or more new values (with possibly a new |
| type) and emit for each new value a record with the same key of the input record and the value.</div> |
| </td> |
| </tr> |
| <tr id="i18" class="altColor"> |
| <td class="colFirst"><code>void</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#foreach-org.apache.kafka.streams.kstream.ForeachAction-">foreach</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ForeachAction.html" title="interface in org.apache.kafka.streams.kstream">ForeachAction</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> action)</code> |
| <div class="block">Perform an action on each record of <code>KStream</code>.</div> |
| </td> |
| </tr> |
| <tr id="i19" class="rowColor"> |
| <td class="colFirst"><code>void</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#foreach-org.apache.kafka.streams.kstream.ForeachAction-org.apache.kafka.streams.kstream.Named-">foreach</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ForeachAction.html" title="interface in org.apache.kafka.streams.kstream">ForeachAction</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> action, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Perform an action on each record of <code>KStream</code>.</div> |
| </td> |
| </tr> |
| <tr id="i20" class="altColor"> |
| <td class="colFirst"><code><KR> <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-">groupBy</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,KR> keySelector)</code> |
| <div class="block">Group the records of this <code>KStream</code> on a new key that is selected using the provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> |
| and default serializers and deserializers.</div> |
| </td> |
| </tr> |
| <tr id="i21" class="rowColor"> |
| <td class="colFirst"><code><KR> <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Grouped-">groupBy</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,KR> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream">Grouped</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> grouped)</code> |
| <div class="block">Group the records of this <code>KStream</code> on a new key that is selected using the provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> |
| and <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>Serde</code></a>s as specified by <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream"><code>Grouped</code></a>.</div> |
| </td> |
| </tr> |
| <tr id="i22" class="altColor"> |
| <td class="colFirst"><code><KR> <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Serialized-">groupBy</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,KR> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Serialized.html" title="class in org.apache.kafka.streams.kstream">Serialized</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> serialized)</code> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> |
| <div class="block"><span class="deprecationComment">since 2.1. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Grouped-"><code>groupBy(KeyValueMapper, Grouped)</code></a> instead</span></div> |
| </div> |
| </td> |
| </tr> |
| <tr id="i23" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupByKey--">groupByKey</a></span>()</code> |
| <div class="block">Group the records by their current key into a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> while preserving the original values |
| and default serializers and deserializers.</div> |
| </td> |
| </tr> |
| <tr id="i24" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupByKey-org.apache.kafka.streams.kstream.Grouped-">groupByKey</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream">Grouped</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> grouped)</code> |
| <div class="block">Group the records by their current key into a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> while preserving the original values |
| and using the serializers as defined by <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream"><code>Grouped</code></a>.</div> |
| </td> |
| </tr> |
| <tr id="i25" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupByKey-org.apache.kafka.streams.kstream.Serialized-">groupByKey</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Serialized.html" title="class in org.apache.kafka.streams.kstream">Serialized</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> serialized)</code> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> |
| <div class="block"><span class="deprecationComment">since 2.1. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupByKey-org.apache.kafka.streams.kstream.Grouped-"><code>groupByKey(Grouped)</code></a> instead</span></div> |
| </div> |
| </td> |
| </tr> |
| <tr id="i26" class="altColor"> |
| <td class="colFirst"><code><GK,GV,RV> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,RV></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-">join</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream">GlobalKTable</a><GK,GV> globalTable, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends GK> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super GV,? extends RV> joiner)</code> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a>'s records using non-windowed inner equi join.</div> |
| </td> |
| </tr> |
| <tr id="i27" class="rowColor"> |
| <td class="colFirst"><code><GK,GV,RV> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,RV></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Named-">join</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream">GlobalKTable</a><GK,GV> globalTable, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends GK> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super GV,? extends RV> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a>'s records using non-windowed inner equi join.</div> |
| </td> |
| </tr> |
| <tr id="i28" class="altColor"> |
| <td class="colFirst"><code><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-">join</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows)</code> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed inner equi join with default |
| serializers and deserializers.</div> |
| </td> |
| </tr> |
| <tr id="i29" class="rowColor"> |
| <td class="colFirst"><code><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-">join</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> joined)</code> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> |
| <div class="block"><span class="deprecationComment">since 2.4. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>join(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a> instead.</span></div> |
| </div> |
| </td> |
| </tr> |
| <tr id="i30" class="altColor"> |
| <td class="colFirst"><code><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-">join</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream">StreamJoined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> streamJoined)</code> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed inner equi join using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream"><code>StreamJoined</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>this stream's value |
| serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>the other stream's value serde</code></a>, and used state stores.</div> |
| </td> |
| </tr> |
| <tr id="i31" class="rowColor"> |
| <td class="colFirst"><code><VT,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-">join</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VT> table, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VT,? extends VR> joiner)</code> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>'s records using non-windowed inner equi join with default |
| serializers and deserializers.</div> |
| </td> |
| </tr> |
| <tr id="i32" class="altColor"> |
| <td class="colFirst"><code><VT,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Joined-">join</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VT> table, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VT,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VT> joined)</code> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>'s records using non-windowed inner equi join with default |
| serializers and deserializers.</div> |
| </td> |
| </tr> |
| <tr id="i33" class="rowColor"> |
| <td class="colFirst"><code><GK,GV,RV> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,RV></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-">leftJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream">GlobalKTable</a><GK,GV> globalTable, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends GK> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super GV,? extends RV> valueJoiner)</code> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a>'s records using non-windowed left equi join.</div> |
| </td> |
| </tr> |
| <tr id="i34" class="altColor"> |
| <td class="colFirst"><code><GK,GV,RV> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,RV></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Named-">leftJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream">GlobalKTable</a><GK,GV> globalTable, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends GK> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super GV,? extends RV> valueJoiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a>'s records using non-windowed left equi join.</div> |
| </td> |
| </tr> |
| <tr id="i35" class="rowColor"> |
| <td class="colFirst"><code><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-">leftJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows)</code> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed left equi join with default |
| serializers and deserializers.</div> |
| </td> |
| </tr> |
| <tr id="i36" class="altColor"> |
| <td class="colFirst"><code><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-">leftJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> joined)</code> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> |
| <div class="block"><span class="deprecationComment">since 2.4. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>leftJoin(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a> instead.</span></div> |
| </div> |
| </td> |
| </tr> |
| <tr id="i37" class="rowColor"> |
| <td class="colFirst"><code><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-">leftJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream">StreamJoined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> streamJoined)</code> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed left equi join using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream"><code>StreamJoined</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>this stream's value |
| serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>the other stream's value serde</code></a>, and used state stores.</div> |
| </td> |
| </tr> |
| <tr id="i38" class="altColor"> |
| <td class="colFirst"><code><VT,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-">leftJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VT> table, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VT,? extends VR> joiner)</code> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>'s records using non-windowed left equi join with default |
| serializers and deserializers.</div> |
| </td> |
| </tr> |
| <tr id="i39" class="rowColor"> |
| <td class="colFirst"><code><VT,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Joined-">leftJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VT> table, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VT,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VT> joined)</code> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>'s records using non-windowed left equi join with default |
| serializers and deserializers.</div> |
| </td> |
| </tr> |
| <tr id="i40" class="altColor"> |
| <td class="colFirst"><code><KR,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-">map</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><? extends KR,? extends VR>> mapper)</code> |
| <div class="block">Transform each record of the input stream into a new record in the output stream (both key and value type can be |
| altered arbitrarily).</div> |
| </td> |
| </tr> |
| <tr id="i41" class="rowColor"> |
| <td class="colFirst"><code><KR,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Named-">map</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><? extends KR,? extends VR>> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Transform each record of the input stream into a new record in the output stream (both key and value type can be |
| altered arbitrarily).</div> |
| </td> |
| </tr> |
| <tr id="i42" class="altColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-">mapValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream">ValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> mapper)</code> |
| <div class="block">Transform the value of each input record into a new value (with possible new type) of the output record.</div> |
| </td> |
| </tr> |
| <tr id="i43" class="rowColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-org.apache.kafka.streams.kstream.Named-">mapValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream">ValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Transform the value of each input record into a new value (with possible new type) of the output record.</div> |
| </td> |
| </tr> |
| <tr id="i44" class="altColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-">mapValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream">ValueMapperWithKey</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> mapper)</code> |
| <div class="block">Transform the value of each input record into a new value (with possible new type) of the output record.</div> |
| </td> |
| </tr> |
| <tr id="i45" class="rowColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-org.apache.kafka.streams.kstream.Named-">mapValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream">ValueMapperWithKey</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Transform the value of each input record into a new value (with possible new type) of the output record.</div> |
| </td> |
| </tr> |
| <tr id="i46" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#merge-org.apache.kafka.streams.kstream.KStream-">merge</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> stream)</code> |
| <div class="block">Merge this stream and the given stream into one larger stream.</div> |
| </td> |
| </tr> |
| <tr id="i47" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#merge-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.Named-">merge</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> stream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Merge this stream and the given stream into one larger stream.</div> |
| </td> |
| </tr> |
| <tr id="i48" class="altColor"> |
| <td class="colFirst"><code><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-">outerJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows)</code> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed outer equi join with default |
| serializers and deserializers.</div> |
| </td> |
| </tr> |
| <tr id="i49" class="rowColor"> |
| <td class="colFirst"><code><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-">outerJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> joined)</code> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> |
| <div class="block"><span class="deprecationComment">since 2.4. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>outerJoin(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a> instead.</span></div> |
| </div> |
| </td> |
| </tr> |
| <tr id="i50" class="altColor"> |
| <td class="colFirst"><code><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-">outerJoin</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream">StreamJoined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> streamJoined)</code> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed outer equi join using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream"><code>StreamJoined</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>this stream's value |
| serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>the other stream's value serde</code></a>, and used state stores.</div> |
| </td> |
| </tr> |
| <tr id="i51" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#peek-org.apache.kafka.streams.kstream.ForeachAction-">peek</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ForeachAction.html" title="interface in org.apache.kafka.streams.kstream">ForeachAction</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> action)</code> |
| <div class="block">Perform an action on each record of <code>KStream</code>.</div> |
| </td> |
| </tr> |
| <tr id="i52" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#peek-org.apache.kafka.streams.kstream.ForeachAction-org.apache.kafka.streams.kstream.Named-">peek</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ForeachAction.html" title="interface in org.apache.kafka.streams.kstream">ForeachAction</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> action, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Perform an action on each record of <code>KStream</code>.</div> |
| </td> |
| </tr> |
| <tr id="i53" class="rowColor"> |
| <td class="colFirst"><code>void</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#print-org.apache.kafka.streams.kstream.Printed-">print</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Printed.html" title="class in org.apache.kafka.streams.kstream">Printed</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> printed)</code> |
| <div class="block">Print the records of this KStream using the options provided by <a href="../../../../../org/apache/kafka/streams/kstream/Printed.html" title="class in org.apache.kafka.streams.kstream"><code>Printed</code></a> |
| Note that this is mainly for debugging/testing purposes, and it will try to flush on each record print.</div> |
| </td> |
| </tr> |
| <tr id="i54" class="altColor"> |
| <td class="colFirst"><code>void</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-">process</a></span>(<a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor">ProcessorSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> processorSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Process all records in this stream, one record at a time, by applying a <a href="../../../../../org/apache/kafka/streams/processor/Processor.html" title="interface in org.apache.kafka.streams.processor"><code>Processor</code></a> (provided by the given |
| <a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorSupplier</code></a>).</div> |
| </td> |
| </tr> |
| <tr id="i55" class="rowColor"> |
| <td class="colFirst"><code>void</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-">process</a></span>(<a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor">ProcessorSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> processorSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Process all records in this stream, one record at a time, by applying a <a href="../../../../../org/apache/kafka/streams/processor/Processor.html" title="interface in org.apache.kafka.streams.processor"><code>Processor</code></a> (provided by the given |
| <a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorSupplier</code></a>).</div> |
| </td> |
| </tr> |
| <tr id="i56" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--">repartition</a></span>()</code> |
| <div class="block">Materialize this stream to an auto-generated repartition topic and create a new <code>KStream</code> |
| from the auto-generated topic using default serializers, deserializers, and producer's <code>DefaultPartitioner</code>.</div> |
| </td> |
| </tr> |
| <tr id="i57" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-">repartition</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream">Repartitioned</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> repartitioned)</code> |
| <div class="block">Materialize this stream to an auto-generated repartition topic and create a new <code>KStream</code> |
| from the auto-generated topic using <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>value serde</code></a>, <a href="../../../../../org/apache/kafka/streams/processor/StreamPartitioner.html" title="interface in org.apache.kafka.streams.processor"><code>StreamPartitioner</code></a>, |
| number of partitions, and topic name part as defined by <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a>.</div> |
| </td> |
| </tr> |
| <tr id="i58" class="altColor"> |
| <td class="colFirst"><code><KR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-">selectKey</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends KR> mapper)</code> |
| <div class="block">Set a new key (with possibly new type) for each input record.</div> |
| </td> |
| </tr> |
| <tr id="i59" class="rowColor"> |
| <td class="colFirst"><code><KR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Named-">selectKey</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends KR> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Set a new key (with possibly new type) for each input record.</div> |
| </td> |
| </tr> |
| <tr id="i60" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#through-java.lang.String-">through</a></span>(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a> topic)</code> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> |
| <div class="block"><span class="deprecationComment">since 2.6; used <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> instead</span></div> |
| </div> |
| </td> |
| </tr> |
| <tr id="i61" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#through-java.lang.String-org.apache.kafka.streams.kstream.Produced-">through</a></span>(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a> topic, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream">Produced</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> produced)</code> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> |
| <div class="block"><span class="deprecationComment">since 2.6; use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> instead</span></div> |
| </div> |
| </td> |
| </tr> |
| <tr id="i62" class="altColor"> |
| <td class="colFirst"><code>void</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#to-java.lang.String-">to</a></span>(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a> topic)</code> |
| <div class="block">Materialize this stream to a topic using default serializers specified in the config and producer's |
| <code>DefaultPartitioner</code>.</div> |
| </td> |
| </tr> |
| <tr id="i63" class="rowColor"> |
| <td class="colFirst"><code>void</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#to-java.lang.String-org.apache.kafka.streams.kstream.Produced-">to</a></span>(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a> topic, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream">Produced</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> produced)</code> |
| <div class="block">Materialize this stream to a topic using the provided <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream"><code>Produced</code></a> instance.</div> |
| </td> |
| </tr> |
| <tr id="i64" class="altColor"> |
| <td class="colFirst"><code>void</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#to-org.apache.kafka.streams.processor.TopicNameExtractor-">to</a></span>(<a href="../../../../../org/apache/kafka/streams/processor/TopicNameExtractor.html" title="interface in org.apache.kafka.streams.processor">TopicNameExtractor</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> topicExtractor)</code> |
| <div class="block">Dynamically materialize this stream to topics using default serializers specified in the config and producer's |
| <code>DefaultPartitioner</code>.</div> |
| </td> |
| </tr> |
| <tr id="i65" class="rowColor"> |
| <td class="colFirst"><code>void</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#to-org.apache.kafka.streams.processor.TopicNameExtractor-org.apache.kafka.streams.kstream.Produced-">to</a></span>(<a href="../../../../../org/apache/kafka/streams/processor/TopicNameExtractor.html" title="interface in org.apache.kafka.streams.processor">TopicNameExtractor</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> topicExtractor, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream">Produced</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> produced)</code> |
| <div class="block">Dynamically materialize this stream to topics using the provided <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream"><code>Produced</code></a> instance.</div> |
| </td> |
| </tr> |
| <tr id="i66" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#toTable--">toTable</a></span>()</code> |
| <div class="block">Convert this stream to a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>.</div> |
| </td> |
| </tr> |
| <tr id="i67" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#toTable-org.apache.kafka.streams.kstream.Materialized-">toTable</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Materialized.html" title="class in org.apache.kafka.streams.kstream">Materialized</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="../../../../../org/apache/kafka/streams/state/KeyValueStore.html" title="interface in org.apache.kafka.streams.state">KeyValueStore</a><org.apache.kafka.common.utils.Bytes,byte[]>> materialized)</code> |
| <div class="block">Convert this stream to a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>.</div> |
| </td> |
| </tr> |
| <tr id="i68" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#toTable-org.apache.kafka.streams.kstream.Named-">toTable</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</code> |
| <div class="block">Convert this stream to a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>.</div> |
| </td> |
| </tr> |
| <tr id="i69" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#toTable-org.apache.kafka.streams.kstream.Named-org.apache.kafka.streams.kstream.Materialized-">toTable</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Materialized.html" title="class in org.apache.kafka.streams.kstream">Materialized</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="../../../../../org/apache/kafka/streams/state/KeyValueStore.html" title="interface in org.apache.kafka.streams.state">KeyValueStore</a><org.apache.kafka.common.utils.Bytes,byte[]>> materialized)</code> |
| <div class="block">Convert this stream to a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>.</div> |
| </td> |
| </tr> |
| <tr id="i70" class="altColor"> |
| <td class="colFirst"><code><K1,V1> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><K1,V1></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-">transform</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">TransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><K1,V1>> transformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform each record of the input stream into zero or one record in the output stream (both key and value type |
| can be altered arbitrarily).</div> |
| </td> |
| </tr> |
| <tr id="i71" class="rowColor"> |
| <td class="colFirst"><code><K1,V1> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><K1,V1></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-">transform</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">TransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><K1,V1>> transformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform each record of the input stream into zero or one record in the output stream (both key and value type |
| can be altered arbitrarily).</div> |
| </td> |
| </tr> |
| <tr id="i72" class="altColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-">transformValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> valueTransformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform the value of each input record into a new value (with possibly a new type) of the output record.</div> |
| </td> |
| </tr> |
| <tr id="i73" class="rowColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-">transformValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> valueTransformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform the value of each input record into a new value (with possibly a new type) of the output record.</div> |
| </td> |
| </tr> |
| <tr id="i74" class="altColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-">transformValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerWithKeySupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> valueTransformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform the value of each input record into a new value (with possibly a new type) of the output record.</div> |
| </td> |
| </tr> |
| <tr id="i75" class="rowColor"> |
| <td class="colFirst"><code><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-">transformValues</a></span>(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerWithKeySupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> valueTransformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</code> |
| <div class="block">Transform the value of each input record into a new value (with possibly a new type) of the output record.</div> |
| </td> |
| </tr> |
| </table> |
| </li> |
| </ul> |
| </li> |
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| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> filter(<a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> predicate)</pre> |
| <div class="block">Create a new <code>KStream</code> that consists of all records of this stream which satisfy the given predicate. |
| All records that do not satisfy the predicate are dropped. |
| This is a stateless record-by-record operation.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>predicate</code> - a filter <a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream"><code>Predicate</code></a> that is applied to each record</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains only those records that satisfy the given predicate</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#filterNot-org.apache.kafka.streams.kstream.Predicate-"><code>filterNot(Predicate)</code></a></dd> |
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| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> filter(<a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> predicate, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Create a new <code>KStream</code> that consists of all records of this stream which satisfy the given predicate. |
| All records that do not satisfy the predicate are dropped. |
| This is a stateless record-by-record operation.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>predicate</code> - a filter <a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream"><code>Predicate</code></a> that is applied to each record</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains only those records that satisfy the given predicate</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#filterNot-org.apache.kafka.streams.kstream.Predicate-"><code>filterNot(Predicate)</code></a></dd> |
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| <div class="block">Create a new <code>KStream</code> that consists all records of this stream which do <em>not</em> satisfy the given |
| predicate. |
| All records that <em>do</em> satisfy the predicate are dropped. |
| This is a stateless record-by-record operation.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>predicate</code> - a filter <a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream"><code>Predicate</code></a> that is applied to each record</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains only those records that do <em>not</em> satisfy the given predicate</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#filter-org.apache.kafka.streams.kstream.Predicate-"><code>filter(Predicate)</code></a></dd> |
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| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> filterNot(<a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> predicate, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Create a new <code>KStream</code> that consists all records of this stream which do <em>not</em> satisfy the given |
| predicate. |
| All records that <em>do</em> satisfy the predicate are dropped. |
| This is a stateless record-by-record operation.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>predicate</code> - a filter <a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream"><code>Predicate</code></a> that is applied to each record</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains only those records that do <em>not</em> satisfy the given predicate</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#filter-org.apache.kafka.streams.kstream.Predicate-"><code>filter(Predicate)</code></a></dd> |
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| <pre><KR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> selectKey(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends KR> mapper)</pre> |
| <div class="block">Set a new key (with possibly new type) for each input record. |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> is applied to each input record and computes a new key for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K':V></code>. |
| This is a stateless record-by-record operation. |
| <p> |
| For example, you can use this transformation to set a key for a key-less input record <code><null,V></code> by |
| extracting a key from the value within your <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a>. The example below computes the new key as the |
| length of the value string. |
| <pre><code> |
| KStream<Byte[], String> keyLessStream = builder.stream("key-less-topic"); |
| KStream<Integer, String> keyedStream = keyLessStream.selectKey(new KeyValueMapper<Byte[], String, Integer> { |
| Integer apply(Byte[] key, String value) { |
| return value.length(); |
| } |
| }); |
| </code></pre> |
| Setting a new key might result in an internal data redistribution if a key based operator (like an aggregation or |
| join) is applied to the result <code>KStream</code>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>KR</code> - the new key type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> that computes a new key for each record</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with new key (possibly of different type) and unmodified value</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
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| <pre><KR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> selectKey(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends KR> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Set a new key (with possibly new type) for each input record. |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> is applied to each input record and computes a new key for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K':V></code>. |
| This is a stateless record-by-record operation. |
| <p> |
| For example, you can use this transformation to set a key for a key-less input record <code><null,V></code> by |
| extracting a key from the value within your <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a>. The example below computes the new key as the |
| length of the value string. |
| <pre><code> |
| KStream<Byte[], String> keyLessStream = builder.stream("key-less-topic"); |
| KStream<Integer, String> keyedStream = keyLessStream.selectKey(new KeyValueMapper<Byte[], String, Integer> { |
| Integer apply(Byte[] key, String value) { |
| return value.length(); |
| } |
| }); |
| </code></pre> |
| Setting a new key might result in an internal data redistribution if a key based operator (like an aggregation or |
| join) is applied to the result <code>KStream</code>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>KR</code> - the new key type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> that computes a new key for each record</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with new key (possibly of different type) and unmodified value</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
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| <pre><KR,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,VR> map(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><? extends KR,? extends VR>> mapper)</pre> |
| <div class="block">Transform each record of the input stream into a new record in the output stream (both key and value type can be |
| altered arbitrarily). |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> is applied to each input record and computes a new output record. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K':V'></code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a> for |
| stateful record transformation). |
| <p> |
| The example below normalizes the String key to upper-case letters and counts the number of token of the value string. |
| <pre><code> |
| KStream<String, String> inputStream = builder.stream("topic"); |
| KStream<String, Integer> outputStream = inputStream.map(new KeyValueMapper<String, String, KeyValue<String, Integer>> { |
| KeyValue<String, Integer> apply(String key, String value) { |
| return new KeyValue<>(key.toUpperCase(), value.split(" ").length); |
| } |
| }); |
| </code></pre> |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> must return a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> type and must not return <code>null</code>. |
| <p> |
| Mapping records might result in an internal data redistribution if a key based operator (like an aggregation or |
| join) is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>KR</code> - the key type of the result stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> that computes a new output record</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with new key and value (possibly both of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="map-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Named-"> |
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| </a> |
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| <h4>map</h4> |
| <pre><KR,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,VR> map(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><? extends KR,? extends VR>> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Transform each record of the input stream into a new record in the output stream (both key and value type can be |
| altered arbitrarily). |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> is applied to each input record and computes a new output record. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K':V'></code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a> for |
| stateful record transformation). |
| <p> |
| The example below normalizes the String key to upper-case letters and counts the number of token of the value string. |
| <pre><code> |
| KStream<String, String> inputStream = builder.stream("topic"); |
| KStream<String, Integer> outputStream = inputStream.map(new KeyValueMapper<String, String, KeyValue<String, Integer>> { |
| KeyValue<String, Integer> apply(String key, String value) { |
| return new KeyValue<>(key.toUpperCase(), value.split(" ").length); |
| } |
| }); |
| </code></pre> |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> must return a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> type and must not return <code>null</code>. |
| <p> |
| Mapping records might result in an internal data redistribution if a key based operator (like an aggregation or |
| join) is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>KR</code> - the key type of the result stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> that computes a new output record</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with new key and value (possibly both of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
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| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> mapValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream">ValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> mapper)</pre> |
| <div class="block">Transform the value of each input record into a new value (with possible new type) of the output record. |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> is applied to each input record value and computes a new value for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K:V'></code>. |
| This is a stateless record-by-record operation (cf. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a> for stateful value transformation). |
| <p> |
| The example below counts the number of token of the value string. |
| <pre><code> |
| KStream<String, String> inputStream = builder.stream("topic"); |
| KStream<String, Integer> outputStream = inputStream.mapValues(new ValueMapper<String, Integer> { |
| Integer apply(String value) { |
| return value.split(" ").length; |
| } |
| }); |
| </code></pre> |
| Setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> that computes a new output value</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with unmodified key and new values (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
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| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> mapValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream">ValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Transform the value of each input record into a new value (with possible new type) of the output record. |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> is applied to each input record value and computes a new value for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K:V'></code>. |
| This is a stateless record-by-record operation (cf. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a> for stateful value transformation). |
| <p> |
| The example below counts the number of token of the value string. |
| <pre><code> |
| KStream<String, String> inputStream = builder.stream("topic"); |
| KStream<String, Integer> outputStream = inputStream.mapValues(new ValueMapper<String, Integer> { |
| Integer apply(String value) { |
| return value.split(" ").length; |
| } |
| }); |
| </code></pre> |
| Setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> that computes a new output value</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with unmodified key and new values (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"> |
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| <h4>mapValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> mapValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream">ValueMapperWithKey</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> mapper)</pre> |
| <div class="block">Transform the value of each input record into a new value (with possible new type) of the output record. |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> is applied to each input record value and computes a new value for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K:V'></code>. |
| This is a stateless record-by-record operation (cf. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a> for stateful value transformation). |
| <p> |
| The example below counts the number of tokens of key and value strings. |
| <pre><code> |
| KStream<String, String> inputStream = builder.stream("topic"); |
| KStream<String, Integer> outputStream = inputStream.mapValues(new ValueMapperWithKey<String, String, Integer> { |
| Integer apply(String readOnlyKey, String value) { |
| return readOnlyKey.split(" ").length + value.split(" ").length; |
| } |
| }); |
| </code></pre> |
| Note that the key is read-only and should not be modified, as this can lead to corrupt partitioning. |
| So, setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> that computes a new output value</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with unmodified key and new values (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-org.apache.kafka.streams.kstream.Named-"> |
| <!-- --> |
| </a> |
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| <h4>mapValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> mapValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream">ValueMapperWithKey</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Transform the value of each input record into a new value (with possible new type) of the output record. |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> is applied to each input record value and computes a new value for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K:V'></code>. |
| This is a stateless record-by-record operation (cf. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a> for stateful value transformation). |
| <p> |
| The example below counts the number of tokens of key and value strings. |
| <pre><code> |
| KStream<String, String> inputStream = builder.stream("topic"); |
| KStream<String, Integer> outputStream = inputStream.mapValues(new ValueMapperWithKey<String, String, Integer> { |
| Integer apply(String readOnlyKey, String value) { |
| return readOnlyKey.split(" ").length + value.split(" ").length; |
| } |
| }); |
| </code></pre> |
| Note that the key is read-only and should not be modified, as this can lead to corrupt partitioning. |
| So, setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> that computes a new output value</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with unmodified key and new values (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
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| </a> |
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| <pre><KR,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,VR> flatMap(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><? extends KR,? extends VR>>> mapper)</pre> |
| <div class="block">Transform each record of the input stream into zero or more records in the output stream (both key and value type |
| can be altered arbitrarily). |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> is applied to each input record and computes zero or more output records. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K':V'>, <K'':V''>, ...</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a> for |
| stateful record transformation). |
| <p> |
| The example below splits input records <code><null:String></code> containing sentences as values into their words |
| and emit a record <code><word:1></code> for each word. |
| <pre><code> |
| KStream<byte[], String> inputStream = builder.stream("topic"); |
| KStream<String, Integer> outputStream = inputStream.flatMap( |
| new KeyValueMapper<byte[], String, Iterable<KeyValue<String, Integer>>> { |
| Iterable<KeyValue<String, Integer>> apply(byte[] key, String value) { |
| String[] tokens = value.split(" "); |
| List<KeyValue<String, Integer>> result = new ArrayList<>(tokens.length); |
| |
| for(String token : tokens) { |
| result.add(new KeyValue<>(token, 1)); |
| } |
| |
| return result; |
| } |
| }); |
| </code></pre> |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> (e.g., any <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) |
| and the return value must not be <code>null</code>. |
| <p> |
| Flat-mapping records might result in an internal data redistribution if a key based operator (like an aggregation |
| or join) is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>KR</code> - the key type of the result stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> that computes the new output records</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with new key and value (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Named-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>flatMap</h4> |
| <pre><KR,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><KR,VR> flatMap(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><? extends KR,? extends VR>>> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Transform each record of the input stream into zero or more records in the output stream (both key and value type |
| can be altered arbitrarily). |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> is applied to each input record and computes zero or more output records. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K':V'>, <K'':V''>, ...</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a> for |
| stateful record transformation). |
| <p> |
| The example below splits input records <code><null:String></code> containing sentences as values into their words |
| and emit a record <code><word:1></code> for each word. |
| <pre><code> |
| KStream<byte[], String> inputStream = builder.stream("topic"); |
| KStream<String, Integer> outputStream = inputStream.flatMap( |
| new KeyValueMapper<byte[], String, Iterable<KeyValue<String, Integer>>> { |
| Iterable<KeyValue<String, Integer>> apply(byte[] key, String value) { |
| String[] tokens = value.split(" "); |
| List<KeyValue<String, Integer>> result = new ArrayList<>(tokens.length); |
| |
| for(String token : tokens) { |
| result.add(new KeyValue<>(token, 1)); |
| } |
| |
| return result; |
| } |
| }); |
| </code></pre> |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> (e.g., any <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) |
| and the return value must not be <code>null</code>. |
| <p> |
| Flat-mapping records might result in an internal data redistribution if a key based operator (like an aggregation |
| or join) is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>KR</code> - the key type of the result stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> that computes the new output records</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with new key and value (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>flatMapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>flatMapValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> flatMapValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream">ValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends VR>> mapper)</pre> |
| <div class="block">Create a new <code>KStream</code> by transforming the value of each record in this stream into zero or more values |
| with the same key in the new stream. |
| Transform the value of each input record into zero or more records with the same (unmodified) key in the output |
| stream (value type can be altered arbitrarily). |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> is applied to each input record and computes zero or more output values. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K:V'>, <K:V''>, ...</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a> |
| for stateful value transformation). |
| <p> |
| The example below splits input records <code><null:String></code> containing sentences as values into their words. |
| <pre><code> |
| KStream<byte[], String> inputStream = builder.stream("topic"); |
| KStream<byte[], String> outputStream = inputStream.flatMapValues(new ValueMapper<String, Iterable<String>> { |
| Iterable<String> apply(String value) { |
| return Arrays.asList(value.split(" ")); |
| } |
| }); |
| </code></pre> |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> (e.g., any <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) |
| and the return value must not be <code>null</code>. |
| <p> |
| Splitting a record into multiple records with the same key preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> the computes the new output values</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with unmodified keys and new values of different type</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatMapValues-org.apache.kafka.streams.kstream.ValueMapper-org.apache.kafka.streams.kstream.Named-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>flatMapValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> flatMapValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream">ValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends VR>> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Create a new <code>KStream</code> by transforming the value of each record in this stream into zero or more values |
| with the same key in the new stream. |
| Transform the value of each input record into zero or more records with the same (unmodified) key in the output |
| stream (value type can be altered arbitrarily). |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> is applied to each input record and computes zero or more output values. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K:V'>, <K:V''>, ...</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a> |
| for stateful value transformation). |
| <p> |
| The example below splits input records <code><null:String></code> containing sentences as values into their words. |
| <pre><code> |
| KStream<byte[], String> inputStream = builder.stream("topic"); |
| KStream<byte[], String> outputStream = inputStream.flatMapValues(new ValueMapper<String, Iterable<String>> { |
| Iterable<String> apply(String value) { |
| return Arrays.asList(value.split(" ")); |
| } |
| }); |
| </code></pre> |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> (e.g., any <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) |
| and the return value must not be <code>null</code>. |
| <p> |
| Splitting a record into multiple records with the same key preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapper</code></a> the computes the new output values</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with unmodified keys and new values of different type</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
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| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> flatMapValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream">ValueMapperWithKey</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends VR>> mapper)</pre> |
| <div class="block">Create a new <code>KStream</code> by transforming the value of each record in this stream into zero or more values |
| with the same key in the new stream. |
| Transform the value of each input record into zero or more records with the same (unmodified) key in the output |
| stream (value type can be altered arbitrarily). |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> is applied to each input record and computes zero or more output values. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K:V'>, <K:V''>, ...</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a> |
| for stateful value transformation). |
| <p> |
| The example below splits input records <code><Integer:String></code>, with key=1, containing sentences as values |
| into their words. |
| <pre><code> |
| KStream<Integer, String> inputStream = builder.stream("topic"); |
| KStream<Integer, String> outputStream = inputStream.flatMapValues(new ValueMapper<Integer, String, Iterable<String>> { |
| Iterable<Integer, String> apply(Integer readOnlyKey, String value) { |
| if(readOnlyKey == 1) { |
| return Arrays.asList(value.split(" ")); |
| } else { |
| return Arrays.asList(value); |
| } |
| } |
| }); |
| </code></pre> |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> (e.g., any <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) |
| and the return value must not be <code>null</code>. |
| <p> |
| Note that the key is read-only and should not be modified, as this can lead to corrupt partitioning. |
| So, splitting a record into multiple records with the same key preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> the computes the new output values</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with unmodified keys and new values of different type</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-org.apache.kafka.streams.kstream.Named-"> |
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| <h4>flatMapValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> flatMapValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream">ValueMapperWithKey</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><? extends VR>> mapper, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Create a new <code>KStream</code> by transforming the value of each record in this stream into zero or more values |
| with the same key in the new stream. |
| Transform the value of each input record into zero or more records with the same (unmodified) key in the output |
| stream (value type can be altered arbitrarily). |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> is applied to each input record and computes zero or more output values. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K:V'>, <K:V''>, ...</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a> |
| for stateful value transformation). |
| <p> |
| The example below splits input records <code><Integer:String></code>, with key=1, containing sentences as values |
| into their words. |
| <pre><code> |
| KStream<Integer, String> inputStream = builder.stream("topic"); |
| KStream<Integer, String> outputStream = inputStream.flatMapValues(new ValueMapper<Integer, String, Iterable<String>> { |
| Iterable<Integer, String> apply(Integer readOnlyKey, String value) { |
| if(readOnlyKey == 1) { |
| return Arrays.asList(value.split(" ")); |
| } else { |
| return Arrays.asList(value); |
| } |
| } |
| }); |
| </code></pre> |
| The provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> (e.g., any <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) |
| and the return value must not be <code>null</code>. |
| <p> |
| Note that the key is read-only and should not be modified, as this can lead to corrupt partitioning. |
| So, splitting a record into multiple records with the same key preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>mapper</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueMapperWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueMapperWithKey</code></a> the computes the new output values</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with unmodified keys and new values of different type</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>flatTransformValues(ValueTransformerWithKeySupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="print-org.apache.kafka.streams.kstream.Printed-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>print</h4> |
| <pre>void print(<a href="../../../../../org/apache/kafka/streams/kstream/Printed.html" title="class in org.apache.kafka.streams.kstream">Printed</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> printed)</pre> |
| <div class="block">Print the records of this KStream using the options provided by <a href="../../../../../org/apache/kafka/streams/kstream/Printed.html" title="class in org.apache.kafka.streams.kstream"><code>Printed</code></a> |
| Note that this is mainly for debugging/testing purposes, and it will try to flush on each record print. |
| It <em>SHOULD NOT</em> be used for production usage if performance requirements are concerned.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>printed</code> - options for printing</dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="foreach-org.apache.kafka.streams.kstream.ForeachAction-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
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| <h4>foreach</h4> |
| <pre>void foreach(<a href="../../../../../org/apache/kafka/streams/kstream/ForeachAction.html" title="interface in org.apache.kafka.streams.kstream">ForeachAction</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> action)</pre> |
| <div class="block">Perform an action on each record of <code>KStream</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a>). |
| Note that this is a terminal operation that returns void.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>action</code> - an action to perform on each record</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="foreach-org.apache.kafka.streams.kstream.ForeachAction-org.apache.kafka.streams.kstream.Named-"> |
| <!-- --> |
| </a> |
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| <h4>foreach</h4> |
| <pre>void foreach(<a href="../../../../../org/apache/kafka/streams/kstream/ForeachAction.html" title="interface in org.apache.kafka.streams.kstream">ForeachAction</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> action, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Perform an action on each record of <code>KStream</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a>). |
| Note that this is a terminal operation that returns void.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>action</code> - an action to perform on each record</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="peek-org.apache.kafka.streams.kstream.ForeachAction-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>peek</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> peek(<a href="../../../../../org/apache/kafka/streams/kstream/ForeachAction.html" title="interface in org.apache.kafka.streams.kstream">ForeachAction</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> action)</pre> |
| <div class="block">Perform an action on each record of <code>KStream</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a>). |
| <p> |
| Peek is a non-terminal operation that triggers a side effect (such as logging or statistics collection) |
| and returns an unchanged stream. |
| <p> |
| Note that since this operation is stateless, it may execute multiple times for a single record in failure cases.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>action</code> - an action to perform on each record</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>itself</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="peek-org.apache.kafka.streams.kstream.ForeachAction-org.apache.kafka.streams.kstream.Named-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>peek</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> peek(<a href="../../../../../org/apache/kafka/streams/kstream/ForeachAction.html" title="interface in org.apache.kafka.streams.kstream">ForeachAction</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> action, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Perform an action on each record of <code>KStream</code>. |
| This is a stateless record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a>). |
| <p> |
| Peek is a non-terminal operation that triggers a side effect (such as logging or statistics collection) |
| and returns an unchanged stream. |
| <p> |
| Note that since this operation is stateless, it may execute multiple times for a single record in failure cases.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>action</code> - an action to perform on each record</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>itself</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="branch-org.apache.kafka.streams.kstream.Predicate...-"> |
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| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>>[] branch(<a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>>... predicates)</pre> |
| <div class="block">Creates an array of <code>KStream</code> from this stream by branching the records in the original stream based on |
| the supplied predicates. |
| Each record is evaluated against the supplied predicates, and predicates are evaluated in order. |
| Each stream in the result array corresponds position-wise (index) to the predicate in the supplied predicates. |
| The branching happens on first-match: A record in the original stream is assigned to the corresponding result |
| stream for the first predicate that evaluates to true, and is assigned to this stream only. |
| A record will be dropped if none of the predicates evaluate to true. |
| This is a stateless record-by-record operation.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>predicates</code> - the ordered list of <a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream"><code>Predicate</code></a> instances</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>multiple distinct substreams of this <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="branch-org.apache.kafka.streams.kstream.Named-org.apache.kafka.streams.kstream.Predicate...-"> |
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| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>>[] branch(<a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream">Predicate</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>>... predicates)</pre> |
| <div class="block">Creates an array of <code>KStream</code> from this stream by branching the records in the original stream based on |
| the supplied predicates. |
| Each record is evaluated against the supplied predicates, and predicates are evaluated in order. |
| Each stream in the result array corresponds position-wise (index) to the predicate in the supplied predicates. |
| The branching happens on first-match: A record in the original stream is assigned to the corresponding result |
| stream for the first predicate that evaluates to true, and is assigned to this stream only. |
| A record will be dropped if none of the predicates evaluate to true. |
| This is a stateless record-by-record operation.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dd><code>predicates</code> - the ordered list of <a href="../../../../../org/apache/kafka/streams/kstream/Predicate.html" title="interface in org.apache.kafka.streams.kstream"><code>Predicate</code></a> instances</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>multiple distinct substreams of this <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="merge-org.apache.kafka.streams.kstream.KStream-"> |
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| <h4>merge</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> merge(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> stream)</pre> |
| <div class="block">Merge this stream and the given stream into one larger stream. |
| <p> |
| There is no ordering guarantee between records from this <code>KStream</code> and records from |
| the provided <code>KStream</code> in the merged stream. |
| Relative order is preserved within each input stream though (ie, records within one input |
| stream are processed in order).</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>stream</code> - a stream which is to be merged into this stream</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a merged stream containing all records from this and the provided <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="merge-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.Named-"> |
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| <h4>merge</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> merge(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> stream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Merge this stream and the given stream into one larger stream. |
| <p> |
| There is no ordering guarantee between records from this <code>KStream</code> and records from |
| the provided <code>KStream</code> in the merged stream. |
| Relative order is preserved within each input stream though (ie, records within one input |
| stream are processed in order).</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>stream</code> - a stream which is to be merged into this stream</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a merged stream containing all records from this and the provided <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="through-java.lang.String-"> |
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| <h4>through</h4> |
| <pre><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Deprecated.html?is-external=true" title="class or interface in java.lang">@Deprecated</a> |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> through(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a> topic)</pre> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> <span class="deprecationComment">since 2.6; used <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> instead</span></div> |
| <div class="block">Materialize this stream to a topic and creates a new <code>KStream</code> from the topic using default serializers, |
| deserializers, and producer's <code>DefaultPartitioner</code>. |
| The specified topic should be manually created before it is used (i.e., before the Kafka Streams application is |
| started). |
| <p> |
| This is similar to calling <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#to-java.lang.String-"><code>#to(someTopicName)</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/StreamsBuilder.html#stream-java.lang.String-"><code>StreamsBuilder#stream(someTopicName)</code></a>. |
| Note that <code>through()</code> uses a hard coded <a href="../../../../../org/apache/kafka/streams/processor/FailOnInvalidTimestamp.html" title="class in org.apache.kafka.streams.processor"><code>timestamp extractor</code></a> and does not allow to customize it, to ensure correct timestamp propagation.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>topic</code> - the topic name</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains the exact same (and potentially repartitioned) records as this <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="through-java.lang.String-org.apache.kafka.streams.kstream.Produced-"> |
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| <h4>through</h4> |
| <pre><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Deprecated.html?is-external=true" title="class or interface in java.lang">@Deprecated</a> |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> through(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a> topic, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream">Produced</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> produced)</pre> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> <span class="deprecationComment">since 2.6; use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> instead</span></div> |
| <div class="block">Materialize this stream to a topic and creates a new <code>KStream</code> from the topic using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream"><code>Produced</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>value serde</code></a>, |
| and <a href="../../../../../org/apache/kafka/streams/processor/StreamPartitioner.html" title="interface in org.apache.kafka.streams.processor"><code>StreamPartitioner</code></a>. |
| The specified topic should be manually created before it is used (i.e., before the Kafka Streams application is |
| started). |
| <p> |
| This is similar to calling <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#to-java.lang.String-org.apache.kafka.streams.kstream.Produced-"><code>to(someTopic, Produced.with(keySerde, valueSerde)</code></a> |
| and <a href="../../../../../org/apache/kafka/streams/StreamsBuilder.html#stream-java.lang.String-org.apache.kafka.streams.kstream.Consumed-"><code>StreamsBuilder#stream(someTopicName, Consumed.with(keySerde, valueSerde))</code></a>. |
| Note that <code>through()</code> uses a hard coded <a href="../../../../../org/apache/kafka/streams/processor/FailOnInvalidTimestamp.html" title="class in org.apache.kafka.streams.processor"><code>timestamp extractor</code></a> and does not allow to customize it, to ensure correct timestamp propagation.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>topic</code> - the topic name</dd> |
| <dd><code>produced</code> - the options to use when producing to the topic</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains the exact same (and potentially repartitioned) records as this <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="repartition--"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>repartition</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> repartition()</pre> |
| <div class="block">Materialize this stream to an auto-generated repartition topic and create a new <code>KStream</code> |
| from the auto-generated topic using default serializers, deserializers, and producer's <code>DefaultPartitioner</code>. |
| The number of partitions is determined based on the upstream topics partition numbers. |
| <p> |
| The created topic is considered as an internal topic and is meant to be used only by the current Kafka Streams instance. |
| Similar to auto-repartitioning, the topic will be created with infinite retention time and data will be automatically purged by Kafka Streams. |
| The topic will be named as "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is an internally generated name, and "-repartition" is a fixed suffix.</div> |
| <dl> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd><code>KStream</code> that contains the exact same repartitioned records as this <code>KStream</code>.</dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="repartition-org.apache.kafka.streams.kstream.Repartitioned-"> |
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| <h4>repartition</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> repartition(<a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream">Repartitioned</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> repartitioned)</pre> |
| <div class="block">Materialize this stream to an auto-generated repartition topic and create a new <code>KStream</code> |
| from the auto-generated topic using <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>value serde</code></a>, <a href="../../../../../org/apache/kafka/streams/processor/StreamPartitioner.html" title="interface in org.apache.kafka.streams.processor"><code>StreamPartitioner</code></a>, |
| number of partitions, and topic name part as defined by <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a>. |
| <p> |
| The created topic is considered as an internal topic and is meant to be used only by the current Kafka Streams instance. |
| Similar to auto-repartitioning, the topic will be created with infinite retention time and data will be automatically purged by Kafka Streams. |
| The topic will be named as "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is either provided via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html#as-java.lang.String-"><code>Repartitioned.as(String)</code></a> or an internally |
| generated name, and "-repartition" is a fixed suffix.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>repartitioned</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> instance used to specify <a href="../../../../../org/apache/kafka/common/serialization/Serdes.html" title="class in org.apache.kafka.common.serialization"><code>Serdes</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/processor/StreamPartitioner.html" title="interface in org.apache.kafka.streams.processor"><code>StreamPartitioner</code></a> which determines how records are distributed among partitions of the topic, |
| part of the topic name, and number of partitions for a repartition topic.</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains the exact same repartitioned records as this <code>KStream</code>.</dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="to-java.lang.String-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
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| <h4>to</h4> |
| <pre>void to(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a> topic)</pre> |
| <div class="block">Materialize this stream to a topic using default serializers specified in the config and producer's |
| <code>DefaultPartitioner</code>. |
| The specified topic should be manually created before it is used (i.e., before the Kafka Streams application is |
| started).</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>topic</code> - the topic name</dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="to-java.lang.String-org.apache.kafka.streams.kstream.Produced-"> |
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| <pre>void to(<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a> topic, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream">Produced</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> produced)</pre> |
| <div class="block">Materialize this stream to a topic using the provided <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream"><code>Produced</code></a> instance. |
| The specified topic should be manually created before it is used (i.e., before the Kafka Streams application is |
| started).</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>topic</code> - the topic name</dd> |
| <dd><code>produced</code> - the options to use when producing to the topic</dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="to-org.apache.kafka.streams.processor.TopicNameExtractor-"> |
| <!-- --> |
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| <h4>to</h4> |
| <pre>void to(<a href="../../../../../org/apache/kafka/streams/processor/TopicNameExtractor.html" title="interface in org.apache.kafka.streams.processor">TopicNameExtractor</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> topicExtractor)</pre> |
| <div class="block">Dynamically materialize this stream to topics using default serializers specified in the config and producer's |
| <code>DefaultPartitioner</code>. |
| The topic names for each record to send to is dynamically determined based on the <a href="../../../../../org/apache/kafka/streams/processor/TopicNameExtractor.html" title="interface in org.apache.kafka.streams.processor"><code>TopicNameExtractor</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>topicExtractor</code> - the extractor to determine the name of the Kafka topic to write to for each record</dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="to-org.apache.kafka.streams.processor.TopicNameExtractor-org.apache.kafka.streams.kstream.Produced-"> |
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| <pre>void to(<a href="../../../../../org/apache/kafka/streams/processor/TopicNameExtractor.html" title="interface in org.apache.kafka.streams.processor">TopicNameExtractor</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> topicExtractor, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream">Produced</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> produced)</pre> |
| <div class="block">Dynamically materialize this stream to topics using the provided <a href="../../../../../org/apache/kafka/streams/kstream/Produced.html" title="class in org.apache.kafka.streams.kstream"><code>Produced</code></a> instance. |
| The topic names for each record to send to is dynamically determined based on the <a href="../../../../../org/apache/kafka/streams/processor/TopicNameExtractor.html" title="interface in org.apache.kafka.streams.processor"><code>TopicNameExtractor</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>topicExtractor</code> - the extractor to determine the name of the Kafka topic to write to for each record</dd> |
| <dd><code>produced</code> - the options to use when producing to the topic</dd> |
| </dl> |
| </li> |
| </ul> |
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| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> toTable()</pre> |
| <div class="block">Convert this stream to a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| <p> |
| If a key changing operator was used before this operation (e.g., <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>) an internal repartitioning topic will be created in Kafka. |
| This topic will be named "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is an internally generated name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| For this case, all data of this stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> is partitioned |
| correctly on its key. |
| Note that you cannot enable <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#TOPOLOGY_OPTIMIZATION_CONFIG"><code>StreamsConfig.TOPOLOGY_OPTIMIZATION_CONFIG</code></a> config for this case, because |
| repartition topics are considered transient and don't allow to recover the result <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> in cause of |
| a failure; hence, a dedicated changelog topic is required to guarantee fault-tolerance. |
| <p> |
| Note that this is a logical operation and only changes the "interpretation" of the stream, i.e., each record of |
| it was a "fact/event" and is re-interpreted as update now (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KStream</code></a> vs <code>KTable</code>).</div> |
| <dl> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> that contains the same records as this <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
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| <h4>toTable</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> toTable(<a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Convert this stream to a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| <p> |
| If a key changing operator was used before this operation (e.g., <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>) an internal repartitioning topic will be created in Kafka. |
| This topic will be named "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is an internally generated name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| For this case, all data of this stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> is partitioned |
| correctly on its key. |
| Note that you cannot enable <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#TOPOLOGY_OPTIMIZATION_CONFIG"><code>StreamsConfig.TOPOLOGY_OPTIMIZATION_CONFIG</code></a> config for this case, because |
| repartition topics are considered transient and don't allow to recover the result <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> in cause of |
| a failure; hence, a dedicated changelog topic is required to guarantee fault-tolerance. |
| <p> |
| Note that this is a logical operation and only changes the "interpretation" of the stream, i.e., each record of |
| it was a "fact/event" and is re-interpreted as update now (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KStream</code></a> vs <code>KTable</code>).</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> that contains the same records as this <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="toTable-org.apache.kafka.streams.kstream.Materialized-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>toTable</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> toTable(<a href="../../../../../org/apache/kafka/streams/kstream/Materialized.html" title="class in org.apache.kafka.streams.kstream">Materialized</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="../../../../../org/apache/kafka/streams/state/KeyValueStore.html" title="interface in org.apache.kafka.streams.state">KeyValueStore</a><org.apache.kafka.common.utils.Bytes,byte[]>> materialized)</pre> |
| <div class="block">Convert this stream to a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| <p> |
| If a key changing operator was used before this operation (e.g., <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>) an internal repartitioning topic will be created in Kafka. |
| This topic will be named "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is an internally generated name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| For this case, all data of this stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> is partitioned |
| correctly on its key. |
| Note that you cannot enable <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#TOPOLOGY_OPTIMIZATION_CONFIG"><code>StreamsConfig.TOPOLOGY_OPTIMIZATION_CONFIG</code></a> config for this case, because |
| repartition topics are considered transient and don't allow to recover the result <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> in cause of |
| a failure; hence, a dedicated changelog topic is required to guarantee fault-tolerance. |
| <p> |
| Note that this is a logical operation and only changes the "interpretation" of the stream, i.e., each record of |
| it was a "fact/event" and is re-interpreted as update now (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KStream</code></a> vs <code>KTable</code>).</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>materialized</code> - an instance of <a href="../../../../../org/apache/kafka/streams/kstream/Materialized.html" title="class in org.apache.kafka.streams.kstream"><code>Materialized</code></a> used to describe how the state store of the |
| resulting table should be materialized.</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> that contains the same records as this <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="toTable-org.apache.kafka.streams.kstream.Named-org.apache.kafka.streams.kstream.Materialized-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>toTable</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> toTable(<a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Materialized.html" title="class in org.apache.kafka.streams.kstream">Materialized</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="../../../../../org/apache/kafka/streams/state/KeyValueStore.html" title="interface in org.apache.kafka.streams.state">KeyValueStore</a><org.apache.kafka.common.utils.Bytes,byte[]>> materialized)</pre> |
| <div class="block">Convert this stream to a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| <p> |
| If a key changing operator was used before this operation (e.g., <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>) an internal repartitioning topic will be created in Kafka. |
| This topic will be named "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is an internally generated name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| For this case, all data of this stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> is partitioned |
| correctly on its key. |
| Note that you cannot enable <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#TOPOLOGY_OPTIMIZATION_CONFIG"><code>StreamsConfig.TOPOLOGY_OPTIMIZATION_CONFIG</code></a> config for this case, because |
| repartition topics are considered transient and don't allow to recover the result <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> in cause of |
| a failure; hence, a dedicated changelog topic is required to guarantee fault-tolerance. |
| <p> |
| Note that this is a logical operation and only changes the "interpretation" of the stream, i.e., each record of |
| it was a "fact/event" and is re-interpreted as update now (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KStream</code></a> vs <code>KTable</code>).</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dd><code>materialized</code> - an instance of <a href="../../../../../org/apache/kafka/streams/kstream/Materialized.html" title="class in org.apache.kafka.streams.kstream"><code>Materialized</code></a> used to describe how the state store of the |
| resulting table should be materialized.</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> that contains the same records as this <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>groupBy</h4> |
| <pre><KR> <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> groupBy(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,KR> keySelector)</pre> |
| <div class="block">Group the records of this <code>KStream</code> on a new key that is selected using the provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> |
| and default serializers and deserializers. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> can be further grouped with other streams to form a <a href="../../../../../org/apache/kafka/streams/kstream/CogroupedKStream.html" title="interface in org.apache.kafka.streams.kstream"><code>CogroupedKStream</code></a>. |
| Grouping a stream on the record key is required before an aggregation operator can be applied to the data |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>). |
| The <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> selects a new key (which may or may not be of the same type) while preserving the |
| original values. |
| If the new record key is <code>null</code> the record will not be included in the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> |
| <p> |
| Because a new key is selected, an internal repartitioning topic may need to be created in Kafka if a |
| later operator depends on the newly selected key. |
| This topic will be named "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is an internally generated name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| All data of this stream will be redistributed through the repartitioning topic by writing all records to it, |
| and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> is partitioned on the new key. |
| <p> |
| This operation is equivalent to calling <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a> followed by <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupByKey--"><code>groupByKey()</code></a>. |
| If the key type is changed, it is recommended to use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Grouped-"><code>groupBy(KeyValueMapper, Grouped)</code></a> instead.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>KR</code> - the key type of the result <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a></dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>keySelector</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> that computes a new key for grouping</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> that contains the grouped records of the original <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Serialized-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
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| <h4>groupBy</h4> |
| <pre><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Deprecated.html?is-external=true" title="class or interface in java.lang">@Deprecated</a> |
| <KR> <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> groupBy(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,KR> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Serialized.html" title="class in org.apache.kafka.streams.kstream">Serialized</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> serialized)</pre> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> <span class="deprecationComment">since 2.1. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Grouped-"><code>groupBy(KeyValueMapper, Grouped)</code></a> instead</span></div> |
| <div class="block">Group the records of this <code>KStream</code> on a new key that is selected using the provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> |
| and <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>Serde</code></a>s as specified by <a href="../../../../../org/apache/kafka/streams/kstream/Serialized.html" title="class in org.apache.kafka.streams.kstream"><code>Serialized</code></a>. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> can be further grouped with other streams to form a <a href="../../../../../org/apache/kafka/streams/kstream/CogroupedKStream.html" title="interface in org.apache.kafka.streams.kstream"><code>CogroupedKStream</code></a>. |
| Grouping a stream on the record key is required before an aggregation operator can be applied to the data |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>). |
| The <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> selects a new key (which may or may not be of the same type) while preserving the |
| original values. |
| If the new record key is <code>null</code> the record will not be included in the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>. |
| <p> |
| Because a new key is selected, an internal repartitioning topic may need to be created in Kafka if a |
| later operator depends on the newly selected key. |
| This topic will be as "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is an internally generated name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| All data of this stream will be redistributed through the repartitioning topic by writing all records to it, |
| and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> is partitioned on the new key. |
| <p> |
| This operation is equivalent to calling <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a> followed by <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupByKey--"><code>groupByKey()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>KR</code> - the key type of the result <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a></dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>keySelector</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> that computes a new key for grouping</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> that contains the grouped records of the original <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.Grouped-"> |
| <!-- --> |
| </a> |
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| <h4>groupBy</h4> |
| <pre><KR> <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> groupBy(<a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,KR> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream">Grouped</a><KR,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> grouped)</pre> |
| <div class="block">Group the records of this <code>KStream</code> on a new key that is selected using the provided <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> |
| and <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>Serde</code></a>s as specified by <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream"><code>Grouped</code></a>. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> can be further grouped with other streams to form a <a href="../../../../../org/apache/kafka/streams/kstream/CogroupedKStream.html" title="interface in org.apache.kafka.streams.kstream"><code>CogroupedKStream</code></a>. |
| Grouping a stream on the record key is required before an aggregation operator can be applied to the data |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>). |
| The <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> selects a new key (which may or may not be of the same type) while preserving the |
| original values. |
| If the new record key is <code>null</code> the record will not be included in the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>. |
| <p> |
| Because a new key is selected, an internal repartitioning topic may need to be created in Kafka if a later |
| operator depends on the newly selected key. |
| This topic will be named "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is either provided via <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html#as-java.lang.String-"><code>Grouped.as(String)</code></a> or an |
| internally generated name. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| All data of this stream will be redistributed through the repartitioning topic by writing all records to it, |
| and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> is partitioned on the new key. |
| <p> |
| This operation is equivalent to calling <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a> followed by <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupByKey--"><code>groupByKey()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>KR</code> - the key type of the result <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a></dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>keySelector</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> that computes a new key for grouping</dd> |
| <dd><code>grouped</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream"><code>Grouped</code></a> instance used to specify <a href="../../../../../org/apache/kafka/common/serialization/Serdes.html" title="class in org.apache.kafka.common.serialization"><code>Serdes</code></a> |
| and part of the name for a repartition topic if repartitioning is required.</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> that contains the grouped records of the original <code>KStream</code></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="groupByKey--"> |
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| <h4>groupByKey</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> groupByKey()</pre> |
| <div class="block">Group the records by their current key into a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> while preserving the original values |
| and default serializers and deserializers. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> can be further grouped with other streams to form a <a href="../../../../../org/apache/kafka/streams/kstream/CogroupedKStream.html" title="interface in org.apache.kafka.streams.kstream"><code>CogroupedKStream</code></a>. |
| Grouping a stream on the record key is required before an aggregation operator can be applied to the data |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>). |
| If a record key is <code>null</code> the record will not be included in the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>. |
| <p> |
| If a key changing operator was used before this operation (e.g., <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>) an internal repartitioning topic may need to be created in |
| Kafka if a later operator depends on the newly selected key. |
| This topic will be named "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is an internally generated name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| For this case, all data of this stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> is partitioned |
| correctly on its key. |
| If the last key changing operator changed the key type, it is recommended to use |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupByKey-org.apache.kafka.streams.kstream.Grouped-"><code>groupByKey(org.apache.kafka.streams.kstream.Grouped)</code></a> instead.</div> |
| <dl> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> that contains the grouped records of the original <code>KStream</code></dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>groupBy(KeyValueMapper)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="groupByKey-org.apache.kafka.streams.kstream.Serialized-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>groupByKey</h4> |
| <pre><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Deprecated.html?is-external=true" title="class or interface in java.lang">@Deprecated</a> |
| <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> groupByKey(<a href="../../../../../org/apache/kafka/streams/kstream/Serialized.html" title="class in org.apache.kafka.streams.kstream">Serialized</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> serialized)</pre> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> <span class="deprecationComment">since 2.1. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupByKey-org.apache.kafka.streams.kstream.Grouped-"><code>groupByKey(Grouped)</code></a> instead</span></div> |
| <div class="block">Group the records by their current key into a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> while preserving the original values |
| and using the serializers as defined by <a href="../../../../../org/apache/kafka/streams/kstream/Serialized.html" title="class in org.apache.kafka.streams.kstream"><code>Serialized</code></a>. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> can be further grouped with other streams to form a <a href="../../../../../org/apache/kafka/streams/kstream/CogroupedKStream.html" title="interface in org.apache.kafka.streams.kstream"><code>CogroupedKStream</code></a>. |
| Grouping a stream on the record key is required before an aggregation operator can be applied to the data |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>). |
| If a record key is <code>null</code> the record will not be included in the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>. |
| <p> |
| If a key changing operator was used before this operation (e.g., <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>) an internal repartitioning topic may need to be created in |
| Kafka if a later operator depends on the newly selected key. |
| This topic will be named "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "<name>" is an internally generated name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| For this case, all data of this stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> is partitioned |
| correctly on its key.</div> |
| <dl> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> that contains the grouped records of the original <code>KStream</code></dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>groupBy(KeyValueMapper)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="groupByKey-org.apache.kafka.streams.kstream.Grouped-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>groupByKey</h4> |
| <pre><a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream">KGroupedStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> groupByKey(<a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream">Grouped</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> grouped)</pre> |
| <div class="block">Group the records by their current key into a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> while preserving the original values |
| and using the serializers as defined by <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream"><code>Grouped</code></a>. |
| <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> can be further grouped with other streams to form a <a href="../../../../../org/apache/kafka/streams/kstream/CogroupedKStream.html" title="interface in org.apache.kafka.streams.kstream"><code>CogroupedKStream</code></a>. |
| Grouping a stream on the record key is required before an aggregation operator can be applied to the data |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>). |
| If a record key is <code>null</code> the record will not be included in the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a>. |
| <p> |
| If a key changing operator was used before this operation (e.g., <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#selectKey-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>selectKey(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>) an internal repartitioning topic may need to be created in |
| Kafka if a later operator depends on the newly selected key. |
| This topic will be named "${applicationId}-<name>-repartition", where "applicationId" is user-specified in |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| <name> is either provided via <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html#as-java.lang.String-"><code>Grouped.as(String)</code></a> or an internally |
| generated name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| For this case, all data of this stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the resulting <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> is partitioned |
| correctly on its key.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>grouped</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/Grouped.html" title="class in org.apache.kafka.streams.kstream"><code>Grouped</code></a> instance used to specify <a href="../../../../../org/apache/kafka/common/serialization/Serdes.html" title="class in org.apache.kafka.common.serialization"><code>Serdes</code></a> |
| and part of the name for a repartition topic if repartitioning is required.</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <a href="../../../../../org/apache/kafka/streams/kstream/KGroupedStream.html" title="interface in org.apache.kafka.streams.kstream"><code>KGroupedStream</code></a> that contains the grouped records of the original <code>KStream</code></dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#groupBy-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>groupBy(KeyValueMapper)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"> |
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| <h4>join</h4> |
| <pre><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> join(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows)</pre> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed inner equi join with default |
| serializers and deserializers. |
| The join is computed on the records' key with join attribute <code>thisKStream.key == otherKStream.key</code>. |
| Furthermore, two records are only joined if their timestamps are close to each other as defined by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a>, i.e., the window defines an additional join predicate on the record timestamps. |
| <p> |
| For each pair of records meeting both join predicates the provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute |
| a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| If an input record key or value is <code>null</code> the record will not be included in the join operation and thus no |
| output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example (assuming all input records belong to the correct windows): |
| <table border='1'> |
| <tr> |
| <th>this</th> |
| <th>other</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td></td> |
| </tr> |
| <tr> |
| <td><K2:B></td> |
| <td><K2:b></td> |
| <td><K2:ValueJoiner(B,b)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K3:c></td> |
| <td></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> (for one input stream) before |
| doing the join and specify the "correct" number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner). |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| Repartitioning can happen for one or both of the joining <code>KStream</code>s. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key. |
| <p> |
| Both of the joining <code>KStream</code>s will be materialized in local state stores with auto-generated store names. |
| For failure and recovery each store will be backed by an internal changelog topic that will be created in Kafka. |
| The changelog topic will be named "${applicationId}-<storename>-changelog", where "applicationId" is user-specified |
| in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "storeName" is an |
| internally generated name, and "-changelog" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VO</code> - the value type of the other stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>otherStream</code> - the <code>KStream</code> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>windows</code> - the specification of the <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key and within the joining window intervals</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>leftJoin(KStream, ValueJoiner, JoinWindows)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>outerJoin(KStream, ValueJoiner, JoinWindows)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-"> |
| <!-- --> |
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| <ul class="blockList"> |
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| <h4>join</h4> |
| <pre><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Deprecated.html?is-external=true" title="class or interface in java.lang">@Deprecated</a> |
| <VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> join(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> joined)</pre> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> <span class="deprecationComment">since 2.4. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>join(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a> instead.</span></div> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed inner equi join using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream"><code>Joined</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>this stream's value serde</code></a>, |
| and <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>the other stream's value serde</code></a>. |
| The join is computed on the records' key with join attribute <code>thisKStream.key == otherKStream.key</code>. |
| Furthermore, two records are only joined if their timestamps are close to each other as defined by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a>, i.e., the window defines an additional join predicate on the record timestamps. |
| <p> |
| For each pair of records meeting both join predicates the provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute |
| a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| If an input record key or value is <code>null</code> the record will not be included in the join operation and thus no |
| output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example (assuming all input records belong to the correct windows): |
| <table border='1'> |
| <tr> |
| <th>this</th> |
| <th>other</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td></td> |
| </tr> |
| <tr> |
| <td><K2:B></td> |
| <td><K2:b></td> |
| <td><K2:ValueJoiner(B,b)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K3:c></td> |
| <td></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> (for one input stream) before |
| doing the join and specify the "correct" number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner). |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| Repartitioning can happen for one or both of the joining <code>KStream</code>s. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key. |
| <p> |
| Both of the joining <code>KStream</code>s will be materialized in local state stores with auto-generated store names. |
| For failure and recovery each store will be backed by an internal changelog topic that will be created in Kafka. |
| The changelog topic will be named "${applicationId}-<storename>-changelog", where "applicationId" is user-specified |
| in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "storeName" is an |
| internally generated name, and "-changelog" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VO</code> - the value type of the other stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>otherStream</code> - the <code>KStream</code> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>windows</code> - the specification of the <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a></dd> |
| <dd><code>joined</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream"><code>Joined</code></a> instance that defines the serdes to |
| be used to serialize/deserialize inputs and outputs of the joined streams</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key and within the joining window intervals</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-"><code>leftJoin(KStream, ValueJoiner, JoinWindows, Joined)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-"><code>outerJoin(KStream, ValueJoiner, JoinWindows, Joined)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>join</h4> |
| <pre><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> join(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream">StreamJoined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> streamJoined)</pre> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed inner equi join using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream"><code>StreamJoined</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>this stream's value |
| serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>the other stream's value serde</code></a>, and used state stores. |
| The join is computed on the records' key with join attribute <code>thisKStream.key == otherKStream.key</code>. |
| Furthermore, two records are only joined if their timestamps are close to each other as defined by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a>, i.e., the window defines an additional join predicate on the record timestamps. |
| <p> |
| For each pair of records meeting both join predicates the provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute |
| a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| If an input record key or value is <code>null</code> the record will not be included in the join operation and thus no |
| output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example (assuming all input records belong to the correct windows): |
| <table border='1'> |
| <tr> |
| <th>this</th> |
| <th>other</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td></td> |
| </tr> |
| <tr> |
| <td><K2:B></td> |
| <td><K2:b></td> |
| <td><K2:ValueJoiner(B,b)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K3:c></td> |
| <td></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> (for one input stream) before |
| doing the join and specify the "correct" number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner). |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| Repartitioning can happen for one or both of the joining <code>KStream</code>s. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key. |
| <p> |
| Both of the joining <code>KStream</code>s will be materialized in local state stores with auto-generated store names, |
| unless a name is provided via a <code>Materialized</code> instance. |
| For failure and recovery each store will be backed by an internal changelog topic that will be created in Kafka. |
| The changelog topic will be named "${applicationId}-<storename>-changelog", where "applicationId" is user-specified |
| in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "storeName" is an |
| internally generated name, and "-changelog" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VO</code> - the value type of the other stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>otherStream</code> - the <code>KStream</code> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>windows</code> - the specification of the <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a></dd> |
| <dd><code>streamJoined</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream"><code>StreamJoined</code></a> used to configure join stores</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key and within the joining window intervals</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>leftJoin(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>outerJoin(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"> |
| <!-- --> |
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| <h4>leftJoin</h4> |
| <pre><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> leftJoin(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows)</pre> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed left equi join with default |
| serializers and deserializers. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>inner-join</code></a>, all records from this stream will |
| produce at least one output record (cf. below). |
| The join is computed on the records' key with join attribute <code>thisKStream.key == otherKStream.key</code>. |
| Furthermore, two records are only joined if their timestamps are close to each other as defined by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a>, i.e., the window defines an additional join predicate on the record timestamps. |
| <p> |
| For each pair of records meeting both join predicates the provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute |
| a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| Furthermore, for each input record of this <code>KStream</code> that does not satisfy the join predicate the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called with a <code>null</code> value for the other stream. |
| If an input record key or value is <code>null</code> the record will not be included in the join operation and thus no |
| output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example (assuming all input records belong to the correct windows): |
| <table border='1'> |
| <tr> |
| <th>this</th> |
| <th>other</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td><K1:ValueJoiner(A,null)></td> |
| </tr> |
| <tr> |
| <td><K2:B></td> |
| <td><K2:b></td> |
| <td><K2:ValueJoiner(B,b)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K3:c></td> |
| <td></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> (for one input stream) before |
| doing the join and specify the "correct" number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner). |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| Repartitioning can happen for one or both of the joining <code>KStream</code>s. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key. |
| <p> |
| Both of the joining <code>KStream</code>s will be materialized in local state stores with auto-generated store names. |
| For failure and recovery each store will be backed by an internal changelog topic that will be created in Kafka. |
| The changelog topic will be named "${applicationId}-<storename>-changelog", where "applicationId" is user-specified |
| in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "storeName" is an internally generated name, and "-changelog" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VO</code> - the value type of the other stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>otherStream</code> - the <code>KStream</code> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>windows</code> - the specification of the <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key plus one for each non-matching record of |
| this <code>KStream</code> and within the joining window intervals</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>join(KStream, ValueJoiner, JoinWindows)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>outerJoin(KStream, ValueJoiner, JoinWindows)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-"> |
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| <h4>leftJoin</h4> |
| <pre><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Deprecated.html?is-external=true" title="class or interface in java.lang">@Deprecated</a> |
| <VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> leftJoin(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> joined)</pre> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> <span class="deprecationComment">since 2.4. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>leftJoin(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a> instead.</span></div> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed left equi join using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream"><code>Joined</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>this stream's value serde</code></a>, |
| and <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>the other stream's value serde</code></a>. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>inner-join</code></a>, all records from this stream will |
| produce at least one output record (cf. below). |
| The join is computed on the records' key with join attribute <code>thisKStream.key == otherKStream.key</code>. |
| Furthermore, two records are only joined if their timestamps are close to each other as defined by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a>, i.e., the window defines an additional join predicate on the record timestamps. |
| <p> |
| For each pair of records meeting both join predicates the provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute |
| a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| Furthermore, for each input record of this <code>KStream</code> that does not satisfy the join predicate the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called with a <code>null</code> value for the other stream. |
| If an input record key or value is <code>null</code> the record will not be included in the join operation and thus no |
| output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example (assuming all input records belong to the correct windows): |
| <table border='1'> |
| <tr> |
| <th>this</th> |
| <th>other</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td><K1:ValueJoiner(A,null)></td> |
| </tr> |
| <tr> |
| <td><K2:B></td> |
| <td><K2:b></td> |
| <td><K2:ValueJoiner(B,b)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K3:c></td> |
| <td></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> (for one input stream) before |
| doing the join and specify the "correct" number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner). |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| Repartitioning can happen for one or both of the joining <code>KStream</code>s. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key. |
| <p> |
| Both of the joining <code>KStream</code>s will be materialized in local state stores with auto-generated store names. |
| For failure and recovery each store will be backed by an internal changelog topic that will be created in Kafka. |
| The changelog topic will be named "${applicationId}-<storename>-changelog", where "applicationId" is user-specified |
| in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "storeName" is an internally generated name, and "-changelog" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VO</code> - the value type of the other stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>otherStream</code> - the <code>KStream</code> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>windows</code> - the specification of the <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a></dd> |
| <dd><code>joined</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream"><code>Joined</code></a> instance that defines the serdes to |
| be used to serialize/deserialize inputs and outputs of the joined streams</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key plus one for each non-matching record of |
| this <code>KStream</code> and within the joining window intervals</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-"><code>join(KStream, ValueJoiner, JoinWindows, Joined)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-"><code>outerJoin(KStream, ValueJoiner, JoinWindows, Joined)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>leftJoin</h4> |
| <pre><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> leftJoin(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream">StreamJoined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> streamJoined)</pre> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed left equi join using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream"><code>StreamJoined</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>this stream's value |
| serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>the other stream's value serde</code></a>, and used state stores. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>inner-join</code></a>, all records from this stream will |
| produce at least one output record (cf. below). |
| The join is computed on the records' key with join attribute <code>thisKStream.key == otherKStream.key</code>. |
| Furthermore, two records are only joined if their timestamps are close to each other as defined by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a>, i.e., the window defines an additional join predicate on the record timestamps. |
| <p> |
| For each pair of records meeting both join predicates the provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute |
| a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| Furthermore, for each input record of this <code>KStream</code> that does not satisfy the join predicate the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called with a <code>null</code> value for the other stream. |
| If an input record key or value is <code>null</code> the record will not be included in the join operation and thus no |
| output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example (assuming all input records belong to the correct windows): |
| <table border='1'> |
| <tr> |
| <th>this</th> |
| <th>other</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td><K1:ValueJoiner(A,null)></td> |
| </tr> |
| <tr> |
| <td><K2:B></td> |
| <td><K2:b></td> |
| <td><K2:ValueJoiner(B,b)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K3:c></td> |
| <td></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> (for one input stream) before |
| doing the join and specify the "correct" number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner). |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| Repartitioning can happen for one or both of the joining <code>KStream</code>s. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key. |
| <p> |
| Both of the joining <code>KStream</code>s will be materialized in local state stores with auto-generated store names, |
| unless a name is provided via a <code>Materialized</code> instance. |
| For failure and recovery each store will be backed by an internal changelog topic that will be created in Kafka. |
| The changelog topic will be named "${applicationId}-<storename>-changelog", where "applicationId" is user-specified |
| in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "storeName" is an internally generated name, and "-changelog" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VO</code> - the value type of the other stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>otherStream</code> - the <code>KStream</code> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>windows</code> - the specification of the <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a></dd> |
| <dd><code>streamJoined</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream"><code>StreamJoined</code></a> instance to configure serdes and state stores</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key plus one for each non-matching record of |
| this <code>KStream</code> and within the joining window intervals</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>join(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>outerJoin(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"> |
| <!-- --> |
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| <h4>outerJoin</h4> |
| <pre><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> outerJoin(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows)</pre> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed outer equi join with default |
| serializers and deserializers. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>inner-join</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>left-join</code></a>, all records from both streams will produce at |
| least one output record (cf. below). |
| The join is computed on the records' key with join attribute <code>thisKStream.key == otherKStream.key</code>. |
| Furthermore, two records are only joined if their timestamps are close to each other as defined by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a>, i.e., the window defines an additional join predicate on the record timestamps. |
| <p> |
| For each pair of records meeting both join predicates the provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute |
| a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| Furthermore, for each input record of both <code>KStream</code>s that does not satisfy the join predicate the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called with a <code>null</code> value for the this/other stream, respectively. |
| If an input record key or value is <code>null</code> the record will not be included in the join operation and thus no |
| output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example (assuming all input records belong to the correct windows): |
| <table border='1'> |
| <tr> |
| <th>this</th> |
| <th>other</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td><K1:ValueJoiner(A,null)></td> |
| </tr> |
| <tr> |
| <td><K2:B></td> |
| <td><K2:b></td> |
| <td><K2:ValueJoiner(null,b)><br></br><K2:ValueJoiner(B,b)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K3:c></td> |
| <td><K3:ValueJoiner(null,c)></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> (for one input stream) before |
| doing the join and specify the "correct" number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner). |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| Repartitioning can happen for one or both of the joining <code>KStream</code>s. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key. |
| <p> |
| Both of the joining <code>KStream</code>s will be materialized in local state stores with auto-generated store names. |
| For failure and recovery each store will be backed by an internal changelog topic that will be created in Kafka. |
| The changelog topic will be named "${applicationId}-<storename>-changelog", where "applicationId" is user-specified |
| in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "storeName" is an internally generated name, and "-changelog" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VO</code> - the value type of the other stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>otherStream</code> - the <code>KStream</code> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>windows</code> - the specification of the <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key plus one for each non-matching record of |
| both <code>KStream</code> and within the joining window intervals</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>join(KStream, ValueJoiner, JoinWindows)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>leftJoin(KStream, ValueJoiner, JoinWindows)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-"> |
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| <h4>outerJoin</h4> |
| <pre><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Deprecated.html?is-external=true" title="class or interface in java.lang">@Deprecated</a> |
| <VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> outerJoin(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> joined)</pre> |
| <div class="block"><span class="deprecatedLabel">Deprecated.</span> <span class="deprecationComment">since 2.4. Use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>outerJoin(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a> instead.</span></div> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed outer equi join using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream"><code>Joined</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>this stream's value serde</code></a>, |
| and <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>the other stream's value serde</code></a>. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>inner-join</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>left-join</code></a>, all records from both streams will produce at |
| least one output record (cf. below). |
| The join is computed on the records' key with join attribute <code>thisKStream.key == otherKStream.key</code>. |
| Furthermore, two records are only joined if their timestamps are close to each other as defined by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a>, i.e., the window defines an additional join predicate on the record timestamps. |
| <p> |
| For each pair of records meeting both join predicates the provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute |
| a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| Furthermore, for each input record of both <code>KStream</code>s that does not satisfy the join predicate the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called with a <code>null</code> value for this/other stream, respectively. |
| If an input record key or value is <code>null</code> the record will not be included in the join operation and thus no |
| output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example (assuming all input records belong to the correct windows): |
| <table border='1'> |
| <tr> |
| <th>this</th> |
| <th>other</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td><K1:ValueJoiner(A,null)></td> |
| </tr> |
| <tr> |
| <td><K2:B></td> |
| <td><K2:b></td> |
| <td><K2:ValueJoiner(null,b)><br></br><K2:ValueJoiner(B,b)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K3:c></td> |
| <td><K3:ValueJoiner(null,c)></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> (for one input stream) before |
| doing the join and specify the "correct" number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner). |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| Repartitioning can happen for one or both of the joining <code>KStream</code>s. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key. |
| <p> |
| Both of the joining <code>KStream</code>s will be materialized in local state stores with auto-generated store names. |
| For failure and recovery each store will be backed by an internal changelog topic that will be created in Kafka. |
| The changelog topic will be named "${applicationId}-<storename>-changelog", where "applicationId" is user-specified |
| in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "storeName" is an internally generated name, and "-changelog" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VO</code> - the value type of the other stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>otherStream</code> - the <code>KStream</code> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>windows</code> - the specification of the <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a></dd> |
| <dd><code>joined</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream"><code>Joined</code></a> instance that defines the serdes to |
| be used to serialize/deserialize inputs and outputs of the joined streams</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key plus one for each non-matching record of |
| both <code>KStream</code> and within the joining window intervals</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-"><code>join(KStream, ValueJoiner, JoinWindows, Joined)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.Joined-"><code>leftJoin(KStream, ValueJoiner, JoinWindows, Joined)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="outerJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"> |
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| <li class="blockList"> |
| <h4>outerJoin</h4> |
| <pre><VO,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> outerJoin(<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VO> otherStream, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VO,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream">JoinWindows</a> windows, |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream">StreamJoined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VO> streamJoined)</pre> |
| <div class="block">Join records of this stream with another <code>KStream</code>'s records using windowed outer equi join using the |
| <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream"><code>StreamJoined</code></a> instance for configuration of the <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>key serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>this stream's value |
| serde</code></a>, <a href="../../../../../org/apache/kafka/common/serialization/Serde.html" title="interface in org.apache.kafka.common.serialization"><code>the other stream's value serde</code></a>, and used state stores. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>inner-join</code></a> or |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-"><code>left-join</code></a>, all records from both streams will produce at |
| least one output record (cf. below). |
| The join is computed on the records' key with join attribute <code>thisKStream.key == otherKStream.key</code>. |
| Furthermore, two records are only joined if their timestamps are close to each other as defined by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a>, i.e., the window defines an additional join predicate on the record timestamps. |
| <p> |
| For each pair of records meeting both join predicates the provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute |
| a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| Furthermore, for each input record of both <code>KStream</code>s that does not satisfy the join predicate the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called with a <code>null</code> value for this/other stream, respectively. |
| If an input record key or value is <code>null</code> the record will not be included in the join operation and thus no |
| output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example (assuming all input records belong to the correct windows): |
| <table border='1'> |
| <tr> |
| <th>this</th> |
| <th>other</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td><K1:ValueJoiner(A,null)></td> |
| </tr> |
| <tr> |
| <td><K2:B></td> |
| <td><K2:b></td> |
| <td><K2:ValueJoiner(null,b)><br></br><K2:ValueJoiner(B,b)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K3:c></td> |
| <td><K3:ValueJoiner(null,c)></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> (for one input stream) before |
| doing the join and specify the "correct" number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner). |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| Repartitioning can happen for one or both of the joining <code>KStream</code>s. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key. |
| <p> |
| Both of the joining <code>KStream</code>s will be materialized in local state stores with auto-generated store names, |
| unless a name is provided via a <code>Materialized</code> instance. |
| For failure and recovery each store will be backed by an internal changelog topic that will be created in Kafka. |
| The changelog topic will be named "${applicationId}-<storename>-changelog", where "applicationId" is user-specified |
| in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, |
| "storeName" is an internally generated name, and "-changelog" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VO</code> - the value type of the other stream</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>otherStream</code> - the <code>KStream</code> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>windows</code> - the specification of the <a href="../../../../../org/apache/kafka/streams/kstream/JoinWindows.html" title="class in org.apache.kafka.streams.kstream"><code>JoinWindows</code></a></dd> |
| <dd><code>streamJoined</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/StreamJoined.html" title="class in org.apache.kafka.streams.kstream"><code>StreamJoined</code></a> instance to configure serdes and state stores</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key plus one for each non-matching record of |
| both <code>KStream</code> and within the joining window intervals</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>join(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KStream-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.JoinWindows-org.apache.kafka.streams.kstream.StreamJoined-"><code>leftJoin(KStream, ValueJoiner, JoinWindows, StreamJoined)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="join-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>join</h4> |
| <pre><VT,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> join(<a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VT> table, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VT,? extends VR> joiner)</pre> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>'s records using non-windowed inner equi join with default |
| serializers and deserializers. |
| The join is a primary key table lookup join with join attribute <code>stream.key == table.key</code>. |
| "Table lookup join" means, that results are only computed if <code>KStream</code> records are processed. |
| This is done by performing a lookup for matching records in the <em>current</em> (i.e., processing time) internal |
| <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> state. |
| In contrast, processing <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> input records will only update the internal <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> state and |
| will not produce any result records. |
| <p> |
| For each <code>KStream</code> record that finds a corresponding record in <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| If an <code>KStream</code> input record key or value is <code>null</code> the record will not be included in the join |
| operation and thus no output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example: |
| <table border='1'> |
| <tr> |
| <th>KStream</th> |
| <th>KTable</th> |
| <th>state</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td></td> |
| <td></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K1:b></td> |
| <td><K1:b></td> |
| <td></td> |
| </tr> |
| <tr> |
| <td><K1:C></td> |
| <td></td> |
| <td><K1:b></td> |
| <td><K1:ValueJoiner(C,b)></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> for this <code>KStream</code> |
| before doing the join, specifying the same number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter as the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner); |
| cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>join(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a>. |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| Repartitioning can happen only for this <code>KStream</code> but not for the provided <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VT</code> - the value type of the table</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>table</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-"><code>leftJoin(KTable, ValueJoiner)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>join(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="join-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Joined-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>join</h4> |
| <pre><VT,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> join(<a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VT> table, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VT,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VT> joined)</pre> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>'s records using non-windowed inner equi join with default |
| serializers and deserializers. |
| The join is a primary key table lookup join with join attribute <code>stream.key == table.key</code>. |
| "Table lookup join" means, that results are only computed if <code>KStream</code> records are processed. |
| This is done by performing a lookup for matching records in the <em>current</em> (i.e., processing time) internal |
| <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> state. |
| In contrast, processing <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> input records will only update the internal <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> state and |
| will not produce any result records. |
| <p> |
| For each <code>KStream</code> record that finds a corresponding record in <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute a value (with arbitrary type) for the result record. |
| The key of the result record is the same as for both joining input records. |
| If an <code>KStream</code> input record key or value is <code>null</code> the record will not be included in the join |
| operation and thus no output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example: |
| <table border='1'> |
| <tr> |
| <th>KStream</th> |
| <th>KTable</th> |
| <th>state</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td></td> |
| <td></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K1:b></td> |
| <td><K1:b></td> |
| <td></td> |
| </tr> |
| <tr> |
| <td><K1:C></td> |
| <td></td> |
| <td><K1:b></td> |
| <td><K1:ValueJoiner(C,b)></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> for this <code>KStream</code> |
| before doing the join, specifying the same number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter as the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner); |
| cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>join(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a>. |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| Repartitioning can happen only for this <code>KStream</code> but not for the provided <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VT</code> - the value type of the table</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>table</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>joined</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream"><code>Joined</code></a> instance that defines the serdes to |
| be used to serialize/deserialize inputs of the joined streams</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one for each matched record-pair with the same key</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Joined-"><code>leftJoin(KTable, ValueJoiner, Joined)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>join(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="leftJoin-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-"> |
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| <pre><VT,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> leftJoin(<a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VT> table, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VT,? extends VR> joiner)</pre> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>'s records using non-windowed left equi join with default |
| serializers and deserializers. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-"><code>inner-join</code></a>, all records from this stream will produce an |
| output record (cf. below). |
| The join is a primary key table lookup join with join attribute <code>stream.key == table.key</code>. |
| "Table lookup join" means, that results are only computed if <code>KStream</code> records are processed. |
| This is done by performing a lookup for matching records in the <em>current</em> (i.e., processing time) internal |
| <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> state. |
| In contrast, processing <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> input records will only update the internal <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> state and |
| will not produce any result records. |
| <p> |
| For each <code>KStream</code> record whether or not it finds a corresponding record in <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute a value (with arbitrary type) for the result record. |
| If no <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> record was found during lookup, a <code>null</code> value will be provided to <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>. |
| The key of the result record is the same as for both joining input records. |
| If an <code>KStream</code> input record key or value is <code>null</code> the record will not be included in the join |
| operation and thus no output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example: |
| <table border='1'> |
| <tr> |
| <th>KStream</th> |
| <th>KTable</th> |
| <th>state</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td></td> |
| <td><K1:ValueJoiner(A,null)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K1:b></td> |
| <td><K1:b></td> |
| <td></td> |
| </tr> |
| <tr> |
| <td><K1:C></td> |
| <td></td> |
| <td><K1:b></td> |
| <td><K1:ValueJoiner(C,b)></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> for this <code>KStream</code> |
| before doing the join, specifying the same number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter as the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner); |
| cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>join(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a>. |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| Repartitioning can happen only for this <code>KStream</code> but not for the provided <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VT</code> - the value type of the table</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>table</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one output for each input <code>KStream</code> record</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-"><code>join(KTable, ValueJoiner)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>leftJoin(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="leftJoin-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Joined-"> |
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| <pre><VT,VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> leftJoin(<a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream">KTable</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VT> table, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super VT,? extends VR> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream">Joined</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,VT> joined)</pre> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>'s records using non-windowed left equi join with default |
| serializers and deserializers. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-"><code>inner-join</code></a>, all records from this stream will produce an |
| output record (cf. below). |
| The join is a primary key table lookup join with join attribute <code>stream.key == table.key</code>. |
| "Table lookup join" means, that results are only computed if <code>KStream</code> records are processed. |
| This is done by performing a lookup for matching records in the <em>current</em> (i.e., processing time) internal |
| <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> state. |
| In contrast, processing <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> input records will only update the internal <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> state and |
| will not produce any result records. |
| <p> |
| For each <code>KStream</code> record whether or not it finds a corresponding record in <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute a value (with arbitrary type) for the result record. |
| If no <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> record was found during lookup, a <code>null</code> value will be provided to <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>. |
| The key of the result record is the same as for both joining input records. |
| If an <code>KStream</code> input record key or value is <code>null</code> the record will not be included in the join |
| operation and thus no output record will be added to the resulting <code>KStream</code>. |
| <p> |
| Example: |
| <table border='1'> |
| <tr> |
| <th>KStream</th> |
| <th>KTable</th> |
| <th>state</th> |
| <th>result</th> |
| </tr> |
| <tr> |
| <td><K1:A></td> |
| <td></td> |
| <td></td> |
| <td><K1:ValueJoiner(A,null)></td> |
| </tr> |
| <tr> |
| <td></td> |
| <td><K1:b></td> |
| <td><K1:b></td> |
| <td></td> |
| </tr> |
| <tr> |
| <td><K1:C></td> |
| <td></td> |
| <td><K1:b></td> |
| <td><K1:ValueJoiner(C,b)></td> |
| </tr> |
| </table> |
| Both input streams (or to be more precise, their underlying source topics) need to have the same number of |
| partitions. |
| If this is not the case, you would need to call <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition-org.apache.kafka.streams.kstream.Repartitioned-"><code>repartition(Repartitioned)</code></a> for this <code>KStream</code> |
| before doing the join, specifying the same number of partitions via <a href="../../../../../org/apache/kafka/streams/kstream/Repartitioned.html" title="class in org.apache.kafka.streams.kstream"><code>Repartitioned</code></a> parameter as the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| Furthermore, both input streams need to be co-partitioned on the join key (i.e., use the same partitioner); |
| cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>join(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a>. |
| If this requirement is not met, Kafka Streams will automatically repartition the data, i.e., it will create an |
| internal repartitioning topic in Kafka and write and re-read the data via this topic before the actual join. |
| The repartitioning topic will be named "${applicationId}-<name>-repartition", where "applicationId" is |
| user-specified in <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html" title="class in org.apache.kafka.streams"><code>StreamsConfig</code></a> via parameter |
| <a href="../../../../../org/apache/kafka/streams/StreamsConfig.html#APPLICATION_ID_CONFIG"><code>APPLICATION_ID_CONFIG</code></a>, "<name>" is an internally generated |
| name, and "-repartition" is a fixed suffix. |
| <p> |
| You can retrieve all generated internal topic names via <a href="../../../../../org/apache/kafka/streams/Topology.html#describe--"><code>Topology.describe()</code></a>. |
| <p> |
| Repartitioning can happen only for this <code>KStream</code> but not for the provided <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a>. |
| For this case, all data of the stream will be redistributed through the repartitioning topic by writing all |
| records to it, and rereading all records from it, such that the join input <code>KStream</code> is partitioned |
| correctly on its key.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VT</code> - the value type of the table</dd> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>table</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/KTable.html" title="interface in org.apache.kafka.streams.kstream"><code>KTable</code></a> to be joined with this stream</dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>joined</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Joined.html" title="class in org.apache.kafka.streams.kstream"><code>Joined</code></a> instance that defines the serdes to |
| be used to serialize/deserialize inputs and outputs of the joined streams</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one output for each input <code>KStream</code> record</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.KTable-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Joined-"><code>join(KTable, ValueJoiner, Joined)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>leftJoin(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
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| <h4>join</h4> |
| <pre><GK,GV,RV> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,RV> join(<a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream">GlobalKTable</a><GK,GV> globalTable, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends GK> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super GV,? extends RV> joiner)</pre> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a>'s records using non-windowed inner equi join. |
| The join is a primary key table lookup join with join attribute |
| <code>keyValueMapper.map(stream.keyValue) == table.key</code>. |
| "Table lookup join" means, that results are only computed if <code>KStream</code> records are processed. |
| This is done by performing a lookup for matching records in the <em>current</em> internal <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> |
| state. |
| In contrast, processing <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> input records will only update the internal <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> |
| state and will not produce any result records. |
| <p> |
| For each <code>KStream</code> record that finds a corresponding record in <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute a value (with arbitrary type) for the result record. |
| The key of the result record is the same as the key of this <code>KStream</code>. |
| If a <code>KStream</code> input record key or value is <code>null</code> the record will not be included in the join |
| operation and thus no output record will be added to the resulting <code>KStream</code>. |
| If <code>keyValueMapper</code> returns <code>null</code> implying no match exists, no output record will be added to the |
| resulting <code>KStream</code>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>GK</code> - the key type of <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>GV</code> - the value type of the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>RV</code> - the value type of the resulting <code>KStream</code></dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>globalTable</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> to be joined with this stream</dd> |
| <dd><code>keySelector</code> - instance of <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> used to map from the (key, value) of this stream |
| to the key of the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one output for each input <code>KStream</code> record</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>leftJoin(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Named-"> |
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| <pre><GK,GV,RV> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,RV> join(<a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream">GlobalKTable</a><GK,GV> globalTable, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends GK> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super GV,? extends RV> joiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a>'s records using non-windowed inner equi join. |
| The join is a primary key table lookup join with join attribute |
| <code>keyValueMapper.map(stream.keyValue) == table.key</code>. |
| "Table lookup join" means, that results are only computed if <code>KStream</code> records are processed. |
| This is done by performing a lookup for matching records in the <em>current</em> internal <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> |
| state. |
| In contrast, processing <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> input records will only update the internal <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> |
| state and will not produce any result records. |
| <p> |
| For each <code>KStream</code> record that finds a corresponding record in <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> the provided |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute a value (with arbitrary type) for the result record. |
| The key of the result record is the same as the key of this <code>KStream</code>. |
| If a <code>KStream</code> input record key or value is <code>null</code> the record will not be included in the join |
| operation and thus no output record will be added to the resulting <code>KStream</code>. |
| If <code>keyValueMapper</code> returns <code>null</code> implying no match exists, no output record will be added to the |
| resulting <code>KStream</code>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>GK</code> - the key type of <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>GV</code> - the value type of the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>RV</code> - the value type of the resulting <code>KStream</code></dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>globalTable</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> to be joined with this stream</dd> |
| <dd><code>keySelector</code> - instance of <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> used to map from the (key, value) of this stream |
| to the key of the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>joiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one output for each input <code>KStream</code> record</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#leftJoin-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>leftJoin(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="leftJoin-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"> |
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| <pre><GK,GV,RV> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,RV> leftJoin(<a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream">GlobalKTable</a><GK,GV> globalTable, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends GK> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super GV,? extends RV> valueJoiner)</pre> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a>'s records using non-windowed left equi join. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>inner-join</code></a>, all records from this stream |
| will produce an output record (cf. below). |
| The join is a primary key table lookup join with join attribute |
| <code>keyValueMapper.map(stream.keyValue) == table.key</code>. |
| "Table lookup join" means, that results are only computed if <code>KStream</code> records are processed. |
| This is done by performing a lookup for matching records in the <em>current</em> internal <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> |
| state. |
| In contrast, processing <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> input records will only update the internal <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> |
| state and will not produce any result records. |
| <p> |
| For each <code>KStream</code> record whether or not it finds a corresponding record in <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> the |
| provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute a value (with arbitrary type) for the result record. |
| The key of the result record is the same as this <code>KStream</code>. |
| If a <code>KStream</code> input record key or value is <code>null</code> the record will not be included in the join |
| operation and thus no output record will be added to the resulting <code>KStream</code>. |
| If <code>keyValueMapper</code> returns <code>null</code> implying no match exists, a <code>null</code> value will be |
| provided to <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>. |
| If no <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> record was found during lookup, a <code>null</code> value will be provided to |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>GK</code> - the key type of <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>GV</code> - the value type of the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>RV</code> - the value type of the resulting <code>KStream</code></dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>globalTable</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> to be joined with this stream</dd> |
| <dd><code>keySelector</code> - instance of <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> used to map from the (key, value) of this stream |
| to the key of the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>valueJoiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one output for each input <code>KStream</code> record</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>join(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="leftJoin-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-org.apache.kafka.streams.kstream.Named-"> |
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| <pre><GK,GV,RV> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,RV> leftJoin(<a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream">GlobalKTable</a><GK,GV> globalTable, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream">KeyValueMapper</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends GK> keySelector, |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream">ValueJoiner</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? super GV,? extends RV> valueJoiner, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named)</pre> |
| <div class="block">Join records of this stream with <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a>'s records using non-windowed left equi join. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>inner-join</code></a>, all records from this stream |
| will produce an output record (cf. below). |
| The join is a primary key table lookup join with join attribute |
| <code>keyValueMapper.map(stream.keyValue) == table.key</code>. |
| "Table lookup join" means, that results are only computed if <code>KStream</code> records are processed. |
| This is done by performing a lookup for matching records in the <em>current</em> internal <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> |
| state. |
| In contrast, processing <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> input records will only update the internal <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> |
| state and will not produce any result records. |
| <p> |
| For each <code>KStream</code> record whether or not it finds a corresponding record in <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> the |
| provided <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> will be called to compute a value (with arbitrary type) for the result record. |
| The key of the result record is the same as this <code>KStream</code>. |
| If a <code>KStream</code> input record key or value is <code>null</code> the record will not be included in the join |
| operation and thus no output record will be added to the resulting <code>KStream</code>. |
| If <code>keyValueMapper</code> returns <code>null</code> implying no match exists, a <code>null</code> value will be |
| provided to <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>. |
| If no <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> record was found during lookup, a <code>null</code> value will be provided to |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>GK</code> - the key type of <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>GV</code> - the value type of the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>RV</code> - the value type of the resulting <code>KStream</code></dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>globalTable</code> - the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a> to be joined with this stream</dd> |
| <dd><code>keySelector</code> - instance of <a href="../../../../../org/apache/kafka/streams/kstream/KeyValueMapper.html" title="interface in org.apache.kafka.streams.kstream"><code>KeyValueMapper</code></a> used to map from the (key, value) of this stream |
| to the key of the <a href="../../../../../org/apache/kafka/streams/kstream/GlobalKTable.html" title="interface in org.apache.kafka.streams.kstream"><code>GlobalKTable</code></a></dd> |
| <dd><code>valueJoiner</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a> that computes the join result for a pair of matching records</dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains join-records for each key and values computed by the given |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueJoiner.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueJoiner</code></a>, one output for each input <code>KStream</code> record</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#join-org.apache.kafka.streams.kstream.GlobalKTable-org.apache.kafka.streams.kstream.KeyValueMapper-org.apache.kafka.streams.kstream.ValueJoiner-"><code>join(GlobalKTable, KeyValueMapper, ValueJoiner)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"> |
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| <h4>transform</h4> |
| <pre><K1,V1> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><K1,V1> transform(<a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">TransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><K1,V1>> transformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform each record of the input stream into zero or one record in the output stream (both key and value type |
| can be altered arbitrarily). |
| A <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a>) is applied to each input record and |
| returns zero or one output record. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K':V'></code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>, |
| the processing progress can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.transform(new TransformerSupplier() { |
| public Transformer get() { |
| return new MyTransformer(); |
| } |
| }, "myTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyTransformerSupplier implements TransformerSupplier { |
| // supply transformer |
| Transformer get() { |
| return new MyTransformer(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.transform(new MyTransformerSupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a> must return a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> type in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>transform()</code></a>. |
| The return value of <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> may be <code>null</code>, |
| in which case no record is emitted. |
| <pre><code> |
| class MyTransformer implements Transformer { |
| private ProcessorContext context; |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.context = context; |
| this.state = context.getStateStore("myTransformState"); |
| // punctuate each second; can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| KeyValue transform(K key, V value) { |
| // can access this.state |
| return new KeyValue(key, value); // can emit a single value via return -- can also be null |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before <code>transform()</code>. |
| <p> |
| Transforming records might result in an internal data redistribution if a key based operator (like an aggregation |
| or join) is applied to the result <code>KStream</code>. |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues()</code></a> ) |
| <p> |
| Note that it is possible to emit multiple records for each input record by using |
| <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>context#forward()</code></a> in |
| <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>. |
| Be aware that a mismatch between the types of the emitted records and the type of the stream would only be |
| detected at runtime. |
| To ensure type-safety at compile-time, <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>context#forward()</code></a> should |
| not be used in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>. |
| If in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> multiple records need to be emitted |
| for each input record, it is recommended to use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>K1</code> - the key type of the new stream</dd> |
| <dd><code>V1</code> - the value type of the new stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>transformerSupplier</code> - an instance of <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a> that generates a <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a></dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with new key and value (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="transform-org.apache.kafka.streams.kstream.TransformerSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>transform</h4> |
| <pre><K1,V1> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><K1,V1> transform(<a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">TransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><K1,V1>> transformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform each record of the input stream into zero or one record in the output stream (both key and value type |
| can be altered arbitrarily). |
| A <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a>) is applied to each input record and |
| returns zero or one output record. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K':V'></code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>, |
| the processing progress can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.transform(new TransformerSupplier() { |
| public Transformer get() { |
| return new MyTransformer(); |
| } |
| }, "myTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyTransformerSupplier implements TransformerSupplier { |
| // supply transformer |
| Transformer get() { |
| return new MyTransformer(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.transform(new MyTransformerSupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a> must return a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> type in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>transform()</code></a>. |
| The return value of <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> may be <code>null</code>, |
| in which case no record is emitted. |
| <pre><code> |
| class MyTransformer implements Transformer { |
| private ProcessorContext context; |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.context = context; |
| this.state = context.getStateStore("myTransformState"); |
| // punctuate each second; can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| KeyValue transform(K key, V value) { |
| // can access this.state |
| return new KeyValue(key, value); // can emit a single value via return -- can also be null |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before <code>transform()</code>. |
| <p> |
| Transforming records might result in an internal data redistribution if a key based operator (like an aggregation |
| or join) is applied to the result <code>KStream</code>. |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues()</code></a> ) |
| <p> |
| Note that it is possible to emit multiple records for each input record by using |
| <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>context#forward()</code></a> in |
| <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>. |
| Be aware that a mismatch between the types of the emitted records and the type of the stream would only be |
| detected at runtime. |
| To ensure type-safety at compile-time, <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>context#forward()</code></a> should |
| not be used in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>. |
| If in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> multiple records need to be emitted |
| for each input record, it is recommended to use <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>K1</code> - the key type of the new stream</dd> |
| <dd><code>V1</code> - the value type of the new stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>transformerSupplier</code> - an instance of <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a> that generates a <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a></dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with new key and value (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#map-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>map(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>flatTransform</h4> |
| <pre><K1,V1> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><K1,V1> flatTransform(<a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">TransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><<a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><K1,V1>>> transformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform each record of the input stream into zero or more records in the output stream (both key and value type |
| can be altered arbitrarily). |
| A <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a>) is applied to each input record and |
| returns zero or more output records. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K':V'>, <K'':V''>, ...</code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a> |
| the processing progress can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.transform(new TransformerSupplier() { |
| public Transformer get() { |
| return new MyTransformer(); |
| } |
| }, "myTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyTransformerSupplier implements TransformerSupplier { |
| // supply transformer |
| Transformer get() { |
| return new MyTransformer(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.flatTransform(new MyTransformerSupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> type (e.g., any <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> |
| type) in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>transform()</code></a>. |
| The return value of <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> may be <code>null</code>, |
| which is equal to returning an empty <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a>, i.e., no records are emitted. |
| <pre><code> |
| class MyTransformer implements Transformer { |
| private ProcessorContext context; |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.context = context; |
| this.state = context.getStateStore("myTransformState"); |
| // punctuate each second; can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| Iterable<KeyValue> transform(K key, V value) { |
| // can access this.state |
| List<KeyValue> result = new ArrayList<>(); |
| for (int i = 0; i < 3; i++) { |
| result.add(new KeyValue(key, value)); |
| } |
| return result; // emits a list of key-value pairs via return |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>flatTransform()</code>. |
| <p> |
| Transforming records might result in an internal data redistribution if a key based operator (like an aggregation |
| or join) is applied to the result <code>KStream</code>. |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues()</code></a>) |
| <p> |
| Note that it is possible to emit records by using <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>context#forward()</code></a> in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>. |
| Be aware that a mismatch between the types of the emitted records and the type of the stream would only be |
| detected at runtime. |
| To ensure type-safety at compile-time, <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>context#forward()</code></a> should |
| not be used in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>K1</code> - the key type of the new stream</dd> |
| <dd><code>V1</code> - the value type of the new stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>transformerSupplier</code> - an instance of <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a> that generates a <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a></dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with new key and value (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>flatTransform</h4> |
| <pre><K1,V1> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><K1,V1> flatTransform(<a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">TransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><<a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams">KeyValue</a><K1,V1>>> transformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform each record of the input stream into zero or more records in the output stream (both key and value type |
| can be altered arbitrarily). |
| A <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a>) is applied to each input record and |
| returns zero or more output records. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K':V'>, <K'':V''>, ...</code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a> |
| the processing progress can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.transform(new TransformerSupplier() { |
| public Transformer get() { |
| return new MyTransformer(); |
| } |
| }, "myTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyTransformerSupplier implements TransformerSupplier { |
| // supply transformer |
| Transformer get() { |
| return new MyTransformer(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.flatTransform(new MyTransformerSupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> type (e.g., any <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> |
| type) in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>transform()</code></a>. |
| The return value of <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> may be <code>null</code>, |
| which is equal to returning an empty <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a>, i.e., no records are emitted. |
| <pre><code> |
| class MyTransformer implements Transformer { |
| private ProcessorContext context; |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.context = context; |
| this.state = context.getStateStore("myTransformState"); |
| // punctuate each second; can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| Iterable<KeyValue> transform(K key, V value) { |
| // can access this.state |
| List<KeyValue> result = new ArrayList<>(); |
| for (int i = 0; i < 3; i++) { |
| result.add(new KeyValue(key, value)); |
| } |
| return result; // emits a list of key-value pairs via return |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>flatTransform()</code>. |
| <p> |
| Transforming records might result in an internal data redistribution if a key based operator (like an aggregation |
| or join) is applied to the result <code>KStream</code>. |
| (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues()</code></a>) |
| <p> |
| Note that it is possible to emit records by using <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>context#forward()</code></a> in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>. |
| Be aware that a mismatch between the types of the emitted records and the type of the stream would only be |
| detected at runtime. |
| To ensure type-safety at compile-time, <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>context#forward()</code></a> should |
| not be used in <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html#transform-K-V-"><code>Transformer#transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a>.</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>K1</code> - the key type of the new stream</dd> |
| <dd><code>V1</code> - the value type of the new stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>transformerSupplier</code> - an instance of <a href="../../../../../org/apache/kafka/streams/kstream/TransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>TransformerSupplier</code></a> that generates a <a href="../../../../../org/apache/kafka/streams/kstream/Transformer.html" title="interface in org.apache.kafka.streams.kstream"><code>Transformer</code></a></dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with new key and value (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMap-org.apache.kafka.streams.kstream.KeyValueMapper-"><code>flatMap(KeyValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"><code>transformValues(ValueTransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"><code>transformValues(ValueTransformerWithKeySupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"><code>process(ProcessorSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>transformValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> transformValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> valueTransformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform the value of each input record into a new value (with possibly a new type) of the output record. |
| A <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a>) is applied to each input |
| record value and computes a new value for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K:V'></code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator.punctuate(long)</code></a> the processing progress |
| can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.transformValues(new ValueTransformerSupplier() { |
| public ValueTransformer get() { |
| return new MyValueTransformer(); |
| } |
| }, "myValueTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyValueTransformerSupplier implements ValueTransformerSupplier { |
| // supply transformer |
| ValueTransformer get() { |
| return new MyValueTransformer(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myValueTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.transformValues(new MyValueTransformerSupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> must return the new value in <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html#transform-V-"><code>transform()</code></a>. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform()</code></a>, no additional <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> |
| pairs can be emitted via <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>ProcessorContext.forward()</code></a>. |
| A <a href="../../../../../org/apache/kafka/streams/errors/StreamsException.html" title="class in org.apache.kafka.streams.errors"><code>StreamsException</code></a> is thrown if the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> tries to |
| emit a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pair. |
| <pre><code> |
| class MyValueTransformer implements ValueTransformer { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myValueTransformState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| NewValueType transform(V value) { |
| // can access this.state |
| return new NewValueType(); // or null |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>transformValues()</code>. |
| <p> |
| Setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>valueTransformerSupplier</code> - a instance of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> that generates a |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a></dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with unmodified key and new values (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="transformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>transformValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> transformValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> valueTransformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform the value of each input record into a new value (with possibly a new type) of the output record. |
| A <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a>) is applied to each input |
| record value and computes a new value for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K:V'></code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator.punctuate(long)</code></a> the processing progress |
| can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.transformValues(new ValueTransformerSupplier() { |
| public ValueTransformer get() { |
| return new MyValueTransformer(); |
| } |
| }, "myValueTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyValueTransformerSupplier implements ValueTransformerSupplier { |
| // supply transformer |
| ValueTransformer get() { |
| return new MyValueTransformer(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myValueTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.transformValues(new MyValueTransformerSupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> must return the new value in <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html#transform-V-"><code>transform()</code></a>. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform()</code></a>, no additional <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> |
| pairs can be emitted via <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>ProcessorContext.forward()</code></a>. |
| A <a href="../../../../../org/apache/kafka/streams/errors/StreamsException.html" title="class in org.apache.kafka.streams.errors"><code>StreamsException</code></a> is thrown if the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> tries to |
| emit a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pair. |
| <pre><code> |
| class MyValueTransformer implements ValueTransformer { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myValueTransformState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| NewValueType transform(V value) { |
| // can access this.state |
| return new NewValueType(); // or null |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>transformValues()</code>. |
| <p> |
| Setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>valueTransformerSupplier</code> - a instance of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> that generates a |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a></dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with unmodified key and new values (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>transformValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> transformValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerWithKeySupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> valueTransformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform the value of each input record into a new value (with possibly a new type) of the output record. |
| A <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a>) is applied to |
| each input record value and computes a new value for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K:V'></code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator.punctuate(long)</code></a> the processing progress |
| can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.transformValues(new ValueTransformerWithKeySupplier() { |
| public ValueTransformer get() { |
| return new MyValueTransformer(); |
| } |
| }, "myValueTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyValueTransformerWithKeySupplier implements ValueTransformerWithKeySupplier { |
| // supply transformer |
| ValueTransformerWithKey get() { |
| return new MyValueTransformerWithKey(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myValueTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.transformValues(new MyValueTransformerWithKeySupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> must return the new value in |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html#transform-K-V-"><code>transform()</code></a>. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>, no additional <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pairs |
| can be emitted via <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>ProcessorContext.forward()</code></a>. |
| A <a href="../../../../../org/apache/kafka/streams/errors/StreamsException.html" title="class in org.apache.kafka.streams.errors"><code>StreamsException</code></a> is thrown if the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> tries |
| to emit a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pair. |
| <pre><code> |
| class MyValueTransformerWithKey implements ValueTransformerWithKey { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myValueTransformState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| NewValueType transform(K readOnlyKey, V value) { |
| // can access this.state and use read-only key |
| return new NewValueType(readOnlyKey); // or null |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>transformValues()</code>. |
| <p> |
| Note that the key is read-only and should not be modified, as this can lead to corrupt partitioning. |
| So, setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>valueTransformerSupplier</code> - a instance of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a> that generates a |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a></dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with unmodified key and new values (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="transformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-"> |
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| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>transformValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> transformValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerWithKeySupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,? extends VR> valueTransformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform the value of each input record into a new value (with possibly a new type) of the output record. |
| A <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a>) is applied to |
| each input record value and computes a new value for it. |
| Thus, an input record <code><K,V></code> can be transformed into an output record <code><K:V'></code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator.punctuate(long)</code></a> the processing progress |
| can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.transformValues(new ValueTransformerWithKeySupplier() { |
| public ValueTransformerWithKey get() { |
| return new MyValueTransformerWithKey(); |
| } |
| }, "myValueTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyValueTransformerWithKeySupplier implements ValueTransformerWithKeySupplier { |
| // supply transformer |
| ValueTransformerWithKey get() { |
| return new MyValueTransformerWithKey(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myValueTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.transformValues(new MyValueTransformerWithKeySupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> must return the new value in |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html#transform-K-V-"><code>transform()</code></a>. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>, no additional <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pairs |
| can be emitted via <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>ProcessorContext.forward()</code></a>. |
| A <a href="../../../../../org/apache/kafka/streams/errors/StreamsException.html" title="class in org.apache.kafka.streams.errors"><code>StreamsException</code></a> is thrown if the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> tries |
| to emit a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pair. |
| <pre><code> |
| class MyValueTransformerWithKey implements ValueTransformerWithKey { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myValueTransformState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| NewValueType transform(K readOnlyKey, V value) { |
| // can access this.state and use read-only key |
| return new NewValueType(readOnlyKey); // or null |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>transformValues()</code>. |
| <p> |
| Note that the key is read-only and should not be modified, as this can lead to corrupt partitioning. |
| So, setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>valueTransformerSupplier</code> - a instance of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a> that generates a |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a></dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains records with unmodified key and new values (possibly of different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
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| <h4>flatTransformValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> flatTransformValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><VR>> valueTransformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform the value of each input record into zero or more new values (with possibly a new |
| type) and emit for each new value a record with the same key of the input record and the value. |
| A <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a>) is applied to each input |
| record value and computes zero or more new values. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K:V'>, <K:V''>, ...</code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a> |
| the processing progress can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.flatTransformValues(new ValueTransformerSupplier() { |
| public ValueTransformer get() { |
| return new MyValueTransformer(); |
| } |
| }, "myValueTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyValueTransformerSupplier implements ValueTransformerSupplier { |
| // supply transformer |
| ValueTransformerWithKey get() { |
| return new MyValueTransformerWithKey(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myValueTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.flatTransformValues(new MyValueTransformer()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> type (e.g., any |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) in <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html#transform-V-"><code>transform()</code></a>. |
| If the return value of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html#transform-V-"><code>ValueTransformer#transform()</code></a> is an empty |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> or <code>null</code>, no records are emitted. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>, no additional <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pairs |
| can be emitted via <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>ProcessorContext.forward()</code></a>. |
| A <a href="../../../../../org/apache/kafka/streams/errors/StreamsException.html" title="class in org.apache.kafka.streams.errors"><code>StreamsException</code></a> is thrown if the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> tries to |
| emit a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pair. |
| <pre><code> |
| class MyValueTransformer implements ValueTransformer { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myValueTransformState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| Iterable<NewValueType> transform(V value) { |
| // can access this.state |
| List<NewValueType> result = new ArrayList<>(); |
| for (int i = 0; i < 3; i++) { |
| result.add(new NewValueType(value)); |
| } |
| return result; // values |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>flatTransformValues()</code>. |
| <p> |
| Setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>valueTransformerSupplier</code> - an instance of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> that generates a |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a></dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with unmodified key and new values (possibly of |
| different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>flatTransformValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> flatTransformValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><VR>> valueTransformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform the value of each input record into zero or more new values (with possibly a new |
| type) and emit for each new value a record with the same key of the input record and the value. |
| A <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a>) is applied to each input |
| record value and computes zero or more new values. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K:V'>, <K:V''>, ...</code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator#punctuate()</code></a> |
| the processing progress can be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.flatTransformValues(new ValueTransformerSupplier() { |
| public ValueTransformer get() { |
| return new MyValueTransformer(); |
| } |
| }, "myValueTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyValueTransformerSupplier implements ValueTransformerSupplier { |
| // supply transformer |
| ValueTransformerWithKey get() { |
| return new MyValueTransformerWithKey(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myValueTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.flatTransformValues(new MyValueTransformer()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> type (e.g., any |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) in <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html#transform-V-"><code>transform()</code></a>. |
| If the return value of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html#transform-V-"><code>ValueTransformer#transform()</code></a> is an empty |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> or <code>null</code>, no records are emitted. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>, no additional <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pairs |
| can be emitted via <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>ProcessorContext.forward()</code></a>. |
| A <a href="../../../../../org/apache/kafka/streams/errors/StreamsException.html" title="class in org.apache.kafka.streams.errors"><code>StreamsException</code></a> is thrown if the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a> tries to |
| emit a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pair. |
| <pre><code> |
| class MyValueTransformer implements ValueTransformer { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myValueTransformState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| Iterable<NewValueType> transform(V value) { |
| // can access this.state |
| List<NewValueType> result = new ArrayList<>(); |
| for (int i = 0; i < 3; i++) { |
| result.add(new NewValueType(value)); |
| } |
| return result; // values |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>flatTransformValues()</code>. |
| <p> |
| Setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>valueTransformerSupplier</code> - an instance of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> that generates a |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformer.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformer</code></a></dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with unmodified key and new values (possibly of |
| different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>flatTransformValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> flatTransformValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerWithKeySupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><VR>> valueTransformerSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform the value of each input record into zero or more new values (with possibly a new |
| type) and emit for each new value a record with the same key of the input record and the value. |
| A <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a>) is applied to |
| each input record value and computes zero or more new values. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K:V'>, <K:V''>, ...</code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator.punctuate(long)</code></a> the processing progress can |
| be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.flatTransformValues(new ValueTransformerWithKeySupplier() { |
| public ValueTransformerWithKey get() { |
| return new MyValueTransformerWithKey(); |
| } |
| }, "myValueTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyValueTransformerWithKeySupplier implements ValueTransformerWithKeySupplier { |
| // supply transformer |
| ValueTransformerWithKey get() { |
| return new MyValueTransformerWithKey(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myValueTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.flatTransformValues(new MyValueTransformerWithKey()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> type (e.g., any |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) in <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html#transform-K-V-"><code>transform()</code></a>. |
| If the return value of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html#transform-K-V-"><code>ValueTransformerWithKey#transform()</code></a> |
| is an empty <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> or <code>null</code>, no records are emitted. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>, no additional <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pairs |
| can be emitted via <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>ProcessorContext.forward()</code></a>. |
| A <a href="../../../../../org/apache/kafka/streams/errors/StreamsException.html" title="class in org.apache.kafka.streams.errors"><code>StreamsException</code></a> is thrown if the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> tries |
| to emit a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pair. |
| <pre><code> |
| class MyValueTransformerWithKey implements ValueTransformerWithKey { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myValueTransformState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| Iterable<NewValueType> transform(K readOnlyKey, V value) { |
| // can access this.state and use read-only key |
| List<NewValueType> result = new ArrayList<>(); |
| for (int i = 0; i < 3; i++) { |
| result.add(new NewValueType(readOnlyKey)); |
| } |
| return result; // values |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>flatTransformValues()</code>. |
| <p> |
| Note that the key is read-only and should not be modified, as this can lead to corrupt partitioning. |
| So, setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>valueTransformerSupplier</code> - a instance of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a> that generates a |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a></dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with unmodified key and new values (possibly of |
| different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="flatTransformValues-org.apache.kafka.streams.kstream.ValueTransformerWithKeySupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>flatTransformValues</h4> |
| <pre><VR> <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="interface in org.apache.kafka.streams.kstream">KStream</a><<a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,VR> flatTransformValues(<a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream">ValueTransformerWithKeySupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>,<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang">Iterable</a><VR>> valueTransformerSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Transform the value of each input record into zero or more new values (with possibly a new |
| type) and emit for each new value a record with the same key of the input record and the value. |
| A <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> (provided by the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a>) is applied to |
| each input record value and computes zero or more new values. |
| Thus, an input record <code><K,V></code> can be transformed into output records <code><K:V'>, <K:V''>, ...</code>. |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues()</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatMapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>flatMapValues()</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator.punctuate(long)</code></a> the processing progress can |
| be observed and additional periodic actions can be performed. |
| <p> |
| In order for the transformer to use state stores, the stores must be added to the topology and connected to the |
| transformer using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the transformer. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.flatTransformValues(new ValueTransformerWithKeySupplier() { |
| public ValueTransformerWithKey get() { |
| return new MyValueTransformerWithKey(); |
| } |
| }, "myValueTransformState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerSupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the transformer. |
| <pre><code> |
| class MyValueTransformerWithKeySupplier implements ValueTransformerWithKeySupplier { |
| // supply transformer |
| ValueTransformerWithKey get() { |
| return new MyValueTransformerWithKey(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated transformer |
| // the store name from the builder ("myValueTransformState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myValueTransformState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.flatTransformValues(new MyValueTransformerWithKey()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| The <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> must return an <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> type (e.g., any |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Collection.html?is-external=true" title="class or interface in java.util"><code>Collection</code></a> type) in <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html#transform-K-V-"><code>transform()</code></a>. |
| If the return value of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html#transform-K-V-"><code>ValueTransformerWithKey#transform()</code></a> |
| is an empty <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html?is-external=true" title="class or interface in java.lang"><code>Iterable</code></a> or <code>null</code>, no records are emitted. |
| In contrast to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform()</code></a> and |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>, no additional <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pairs |
| can be emitted via <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html#forward-K-V-"><code>ProcessorContext.forward()</code></a>. |
| A <a href="../../../../../org/apache/kafka/streams/errors/StreamsException.html" title="class in org.apache.kafka.streams.errors"><code>StreamsException</code></a> is thrown if the <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a> tries |
| to emit a <a href="../../../../../org/apache/kafka/streams/KeyValue.html" title="class in org.apache.kafka.streams"><code>KeyValue</code></a> pair. |
| <pre><code> |
| class MyValueTransformerWithKey implements ValueTransformerWithKey { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myValueTransformState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| Iterable<NewValueType> transform(K readOnlyKey, V value) { |
| // can access this.state and use read-only key |
| List<NewValueType> result = new ArrayList<>(); |
| for (int i = 0; i < 3; i++) { |
| result.add(new NewValueType(readOnlyKey)); |
| } |
| return result; // values |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before |
| <code>flatTransformValues()</code>. |
| <p> |
| Note that the key is read-only and should not be modified, as this can lead to corrupt partitioning. |
| So, setting a new value preserves data co-location with respect to the key. |
| Thus, <em>no</em> internal data redistribution is required if a key based operator (like an aggregation or join) |
| is applied to the result <code>KStream</code>. (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform()</code></a>)</div> |
| <dl> |
| <dt><span class="paramLabel">Type Parameters:</span></dt> |
| <dd><code>VR</code> - the value type of the result stream</dd> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>valueTransformerSupplier</code> - a instance of <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKeySupplier.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKeySupplier</code></a> that generates a |
| <a href="../../../../../org/apache/kafka/streams/kstream/ValueTransformerWithKey.html" title="interface in org.apache.kafka.streams.kstream"><code>ValueTransformerWithKey</code></a></dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="returnLabel">Returns:</span></dt> |
| <dd>a <code>KStream</code> that contains more or less records with unmodified key and new values (possibly of |
| different type)</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapper-"><code>mapValues(ValueMapper)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#mapValues-org.apache.kafka.streams.kstream.ValueMapperWithKey-"><code>mapValues(ValueMapperWithKey)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#flatTransform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>flatTransform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="process-org.apache.kafka.streams.processor.ProcessorSupplier-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockList"> |
| <li class="blockList"> |
| <h4>process</h4> |
| <pre>void process(<a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor">ProcessorSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> processorSupplier, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Process all records in this stream, one record at a time, by applying a <a href="../../../../../org/apache/kafka/streams/processor/Processor.html" title="interface in org.apache.kafka.streams.processor"><code>Processor</code></a> (provided by the given |
| <a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorSupplier</code></a>). |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#foreach-org.apache.kafka.streams.kstream.ForeachAction-"><code>foreach(ForeachAction)</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#foreach-org.apache.kafka.streams.kstream.ForeachAction-"><code>foreach(ForeachAction)</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator.punctuate(long)</code></a> the processing progress |
| can be observed and additional periodic actions can be performed. |
| Note that this is a terminal operation that returns void. |
| <p> |
| In order for the processor to use state stores, the stores must be added to the topology and connected to the |
| processor using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the processor. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myProcessorState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.processor(new ProcessorSupplier() { |
| public Processor get() { |
| return new MyProcessor(); |
| } |
| }, "myProcessorState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the processor. |
| <pre><code> |
| class MyProcessorSupplier implements ProcessorSupplier { |
| // supply processor |
| Processor get() { |
| return new MyProcessor(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated processor |
| // the store name from the builder ("myProcessorState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myProcessorState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.process(new MyProcessorSupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/processor/Processor.html" title="interface in org.apache.kafka.streams.processor"><code>Processor</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| <pre><code> |
| class MyProcessor implements Processor { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myProcessorState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| void process(K key, V value) { |
| // can access this.state |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before <code>process()</code>.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>processorSupplier</code> - a instance of <a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorSupplier</code></a> that generates a <a href="../../../../../org/apache/kafka/streams/processor/Processor.html" title="interface in org.apache.kafka.streams.processor"><code>Processor</code></a></dd> |
| <dd><code>stateStoreNames</code> - the names of the state stores used by the processor; not required if the supplier |
| implements <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a></dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#foreach-org.apache.kafka.streams.kstream.ForeachAction-"><code>foreach(ForeachAction)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="process-org.apache.kafka.streams.processor.ProcessorSupplier-org.apache.kafka.streams.kstream.Named-java.lang.String...-"> |
| <!-- --> |
| </a> |
| <ul class="blockListLast"> |
| <li class="blockList"> |
| <h4>process</h4> |
| <pre>void process(<a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor">ProcessorSupplier</a><? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">K</a>,? super <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html" title="type parameter in KStream">V</a>> processorSupplier, |
| <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream">Named</a> named, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>... stateStoreNames)</pre> |
| <div class="block">Process all records in this stream, one record at a time, by applying a <a href="../../../../../org/apache/kafka/streams/processor/Processor.html" title="interface in org.apache.kafka.streams.processor"><code>Processor</code></a> (provided by the given |
| <a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorSupplier</code></a>). |
| Attaching a state store makes this a stateful record-by-record operation (cf. <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#foreach-org.apache.kafka.streams.kstream.ForeachAction-"><code>foreach(ForeachAction)</code></a>). |
| If you choose not to attach one, this operation is similar to the stateless <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#foreach-org.apache.kafka.streams.kstream.ForeachAction-"><code>foreach(ForeachAction)</code></a> |
| but allows access to the <code>ProcessorContext</code> and record metadata. |
| This is essentially mixing the Processor API into the DSL, and provides all the functionality of the PAPI. |
| Furthermore, via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>Punctuator.punctuate(long)</code></a> the processing progress |
| can be observed and additional periodic actions can be performed. |
| Note that this is a terminal operation that returns void. |
| <p> |
| In order for the processor to use state stores, the stores must be added to the topology and connected to the |
| processor using at least one of two strategies (though it's not required to connect global state stores; read-only |
| access to global state stores is available by default). |
| <p> |
| The first strategy is to manually add the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s via <a href="../../../../../org/apache/kafka/streams/Topology.html#addStateStore-org.apache.kafka.streams.state.StoreBuilder-java.lang.String...-"><code>Topology.addStateStore(StoreBuilder, String...)</code></a>, |
| and specify the store names via <code>stateStoreNames</code> so they will be connected to the processor. |
| <pre><code> |
| // create store |
| StoreBuilder<KeyValueStore<String,String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myProcessorState"), |
| Serdes.String(), |
| Serdes.String()); |
| // add store |
| builder.addStateStore(keyValueStoreBuilder); |
| |
| KStream outputStream = inputStream.processor(new ProcessorSupplier() { |
| public Processor get() { |
| return new MyProcessor(); |
| } |
| }, "myProcessorState"); |
| </code></pre> |
| The second strategy is for the given <a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorSupplier</code></a> to implement <a href="../../../../../org/apache/kafka/streams/processor/ConnectedStoreProvider.html#stores--"><code>ConnectedStoreProvider.stores()</code></a>, |
| which provides the <a href="../../../../../org/apache/kafka/streams/state/StoreBuilder.html" title="interface in org.apache.kafka.streams.state"><code>StoreBuilder</code></a>s to be automatically added to the topology and connected to the processor. |
| <pre><code> |
| class MyProcessorSupplier implements ProcessorSupplier { |
| // supply processor |
| Processor get() { |
| return new MyProcessor(); |
| } |
| |
| // provide store(s) that will be added and connected to the associated processor |
| // the store name from the builder ("myProcessorState") is used to access the store later via the ProcessorContext |
| Set<StoreBuilder> stores() { |
| StoreBuilder<KeyValueStore<String, String>> keyValueStoreBuilder = |
| Stores.keyValueStoreBuilder(Stores.persistentKeyValueStore("myProcessorState"), |
| Serdes.String(), |
| Serdes.String()); |
| return Collections.singleton(keyValueStoreBuilder); |
| } |
| } |
| |
| ... |
| |
| KStream outputStream = inputStream.process(new MyProcessorSupplier()); |
| </code></pre> |
| <p> |
| With either strategy, within the <a href="../../../../../org/apache/kafka/streams/processor/Processor.html" title="interface in org.apache.kafka.streams.processor"><code>Processor</code></a>, the state is obtained via the <a href="../../../../../org/apache/kafka/streams/processor/ProcessorContext.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorContext</code></a>. |
| To trigger periodic actions via <a href="../../../../../org/apache/kafka/streams/processor/Punctuator.html#punctuate-long-"><code>punctuate()</code></a>, |
| a schedule must be registered. |
| <pre><code> |
| class MyProcessor implements Processor { |
| private StateStore state; |
| |
| void init(ProcessorContext context) { |
| this.state = context.getStateStore("myProcessorState"); |
| // punctuate each second, can access this.state |
| context.schedule(Duration.ofSeconds(1), PunctuationType.WALL_CLOCK_TIME, new Punctuator(..)); |
| } |
| |
| void process(K key, V value) { |
| // can access this.state |
| } |
| |
| void close() { |
| // can access this.state |
| } |
| } |
| </code></pre> |
| Even if any upstream operation was key-changing, no auto-repartition is triggered. |
| If repartitioning is required, a call to <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#repartition--"><code>repartition()</code></a> should be performed before <code>process()</code>.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>processorSupplier</code> - a instance of <a href="../../../../../org/apache/kafka/streams/processor/ProcessorSupplier.html" title="interface in org.apache.kafka.streams.processor"><code>ProcessorSupplier</code></a> that generates a <a href="../../../../../org/apache/kafka/streams/processor/Processor.html" title="interface in org.apache.kafka.streams.processor"><code>Processor</code></a></dd> |
| <dd><code>named</code> - a <a href="../../../../../org/apache/kafka/streams/kstream/Named.html" title="class in org.apache.kafka.streams.kstream"><code>Named</code></a> config used to name the processor in the topology</dd> |
| <dd><code>stateStoreNames</code> - the names of the state store used by the processor</dd> |
| <dt><span class="seeLabel">See Also:</span></dt> |
| <dd><a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#foreach-org.apache.kafka.streams.kstream.ForeachAction-"><code>foreach(ForeachAction)</code></a>, |
| <a href="../../../../../org/apache/kafka/streams/kstream/KStream.html#transform-org.apache.kafka.streams.kstream.TransformerSupplier-java.lang.String...-"><code>transform(TransformerSupplier, String...)</code></a></dd> |
| </dl> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </div> |
| </div> |
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