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<h1 class="title">Gearpump Connectors</h1>
<h2 id="basic-concepts">Basic Concepts</h2>
<p><code>DataSource</code> and <code>DataSink</code> are the two main concepts Gearpump use to connect with the outside world.</p>
<h3 id="datasource">DataSource</h3>
<p><code>DataSource</code> is the start point of a streaming processing flow.</p>
<h3 id="datasink">DataSink</h3>
<p><code>DataSink</code> is the end point of a streaming processing flow.</p>
<h2 id="implemented-connectors">Implemented Connectors</h2>
<h3 id="datasource-implemented"><code>DataSource</code> implemented</h3>
<p>Currently, we have following <code>DataSource</code> supported.</p>
<table>
<thead>
<tr>
<th>Name</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>CollectionDataSource</code></td>
<td>Convert a collection to a recursive data source. E.g. <code>seq(1, 2, 3)</code> will output <code>1,2,3,1,2,3...</code>.</td>
</tr>
<tr>
<td><code>KafkaSource</code></td>
<td>Read from Kafka.</td>
</tr>
</tbody>
</table>
<h3 id="datasink-implemented"><code>DataSink</code> implemented</h3>
<p>Currently, we have following <code>DataSink</code> supported.</p>
<table>
<thead>
<tr>
<th>Name</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>HBaseSink</code></td>
<td>Write the message to HBase. The message to write must be HBase <code>Put</code> or a tuple of <code>(rowKey, family, column, value)</code>.</td>
</tr>
<tr>
<td><code>KafkaSink</code></td>
<td>Write to Kafka.</td>
</tr>
</tbody>
</table>
<h2 id="use-of-connectors">Use of Connectors</h2>
<h3 id="use-of-kafka-connectors">Use of Kafka connectors</h3>
<p>To use Kafka connectors in your application, you first need to add the <code>gearpump-external-kafka</code> library dependency in your application:</p>
<div class="codetabs">
<div data-lang="sbt" data-label="sbt">
<div class="highlight"><pre><code>"org.apache.gearpump" %% "gearpump-external-kafka" % 0.8.1
</code></pre></div>
</div>
<div data-lang="xml" data-label="xml">
<div class="highlight"><pre><code class="language-xml"><span class="nt">&lt;dependency&gt;</span>
<span class="nt">&lt;groupId&gt;</span>org.apache.gearpump<span class="nt">&lt;/groupId&gt;</span>
<span class="nt">&lt;artifactId&gt;</span>gearpump-external-kafka<span class="nt">&lt;/artifactId&gt;</span>
<span class="nt">&lt;version&gt;</span>0.8.1<span class="nt">&lt;/version&gt;</span>
<span class="nt">&lt;/dependency&gt;</span></code></pre></div>
</div>
</div>
<p>This is a simple example to read from Kafka and write it back using <code>KafkaSource</code> and <code>KafkaSink</code>. Users can optionally set a <code>CheckpointStoreFactory</code> such that Kafka offsets are checkpointed and at-least-once message delivery is guaranteed.</p>
<div class="codetabs">
<div data-lang="scala" data-label="Processor API">
<div class="highlight"><pre><code class="language-scala"> <span class="k">val</span> <span class="n">appConfig</span> <span class="k">=</span> <span class="nc">UserConfig</span><span class="o">.</span><span class="n">empty</span>
<span class="k">val</span> <span class="n">props</span> <span class="k">=</span> <span class="k">new</span> <span class="nc">Properties</span>
<span class="n">props</span><span class="o">.</span><span class="n">put</span><span class="o">(</span><span class="nc">KafkaConfig</span><span class="o">.</span><span class="nc">ZOOKEEPER_CONNECT_CONFIG</span><span class="o">,</span> <span class="n">zookeeperConnect</span><span class="o">)</span>
<span class="n">props</span><span class="o">.</span><span class="n">put</span><span class="o">(</span><span class="nc">KafkaConfig</span><span class="o">.</span><span class="nc">BOOTSTRAP_SERVERS_CONFIG</span><span class="o">,</span> <span class="n">brokerList</span><span class="o">)</span>
<span class="n">props</span><span class="o">.</span><span class="n">put</span><span class="o">(</span><span class="nc">KafkaConfig</span><span class="o">.</span><span class="nc">CHECKPOINT_STORE_NAME_PREFIX_CONFIG</span><span class="o">,</span> <span class="n">appName</span><span class="o">)</span>
<span class="k">val</span> <span class="n">source</span> <span class="k">=</span> <span class="k">new</span> <span class="nc">KafkaSource</span><span class="o">(</span><span class="n">sourceTopic</span><span class="o">,</span> <span class="n">props</span><span class="o">)</span>
<span class="k">val</span> <span class="n">checkpointStoreFactory</span> <span class="k">=</span> <span class="k">new</span> <span class="nc">KafkaStoreFactory</span><span class="o">(</span><span class="n">props</span><span class="o">)</span>
<span class="n">source</span><span class="o">.</span><span class="n">setCheckpointStore</span><span class="o">(</span><span class="n">checkpointStoreFactory</span><span class="o">)</span>
<span class="k">val</span> <span class="n">sourceProcessor</span> <span class="k">=</span> <span class="nc">DataSourceProcessor</span><span class="o">(</span><span class="n">source</span><span class="o">,</span> <span class="n">sourceNum</span><span class="o">)</span>
<span class="k">val</span> <span class="n">sink</span> <span class="k">=</span> <span class="k">new</span> <span class="nc">KafkaSink</span><span class="o">(</span><span class="n">sinkTopic</span><span class="o">,</span> <span class="n">props</span><span class="o">)</span>
<span class="k">val</span> <span class="n">sinkProcessor</span> <span class="k">=</span> <span class="nc">DataSinkProcessor</span><span class="o">(</span><span class="n">sink</span><span class="o">,</span> <span class="n">sinkNum</span><span class="o">)</span>
<span class="k">val</span> <span class="n">partitioner</span> <span class="k">=</span> <span class="k">new</span> <span class="nc">ShufflePartitioner</span>
<span class="k">val</span> <span class="n">computation</span> <span class="k">=</span> <span class="n">sourceProcessor</span> <span class="o">~</span> <span class="n">partitioner</span> <span class="o">~&gt;</span> <span class="n">sinkProcessor</span>
<span class="k">val</span> <span class="n">app</span> <span class="k">=</span> <span class="nc">StreamApplication</span><span class="o">(</span><span class="n">appName</span><span class="o">,</span> <span class="nc">Graph</span><span class="o">(</span><span class="n">computation</span><span class="o">),</span> <span class="n">appConfig</span><span class="o">)</span></code></pre></div>
</div>
<div data-lang="scala" data-label="Stream DSL">
<div class="highlight"><pre><code class="language-scala"> <span class="k">val</span> <span class="n">props</span> <span class="k">=</span> <span class="k">new</span> <span class="nc">Properties</span>
<span class="k">val</span> <span class="n">appName</span> <span class="k">=</span> <span class="s">&quot;KafkaDSL&quot;</span>
<span class="n">props</span><span class="o">.</span><span class="n">put</span><span class="o">(</span><span class="nc">KafkaConfig</span><span class="o">.</span><span class="nc">ZOOKEEPER_CONNECT_CONFIG</span><span class="o">,</span> <span class="n">zookeeperConnect</span><span class="o">)</span>
<span class="n">props</span><span class="o">.</span><span class="n">put</span><span class="o">(</span><span class="nc">KafkaConfig</span><span class="o">.</span><span class="nc">BOOTSTRAP_SERVERS_CONFIG</span><span class="o">,</span> <span class="n">brokerList</span><span class="o">)</span>
<span class="n">props</span><span class="o">.</span><span class="n">put</span><span class="o">(</span><span class="nc">KafkaConfig</span><span class="o">.</span><span class="nc">CHECKPOINT_STORE_NAME_PREFIX_CONFIG</span><span class="o">,</span> <span class="n">appName</span><span class="o">)</span>
<span class="k">val</span> <span class="n">app</span> <span class="k">=</span> <span class="nc">StreamApp</span><span class="o">(</span><span class="n">appName</span><span class="o">,</span> <span class="n">context</span><span class="o">)</span>
<span class="k">if</span> <span class="o">(</span><span class="n">atLeastOnce</span><span class="o">)</span> <span class="o">{</span>
<span class="k">val</span> <span class="n">checkpointStoreFactory</span> <span class="k">=</span> <span class="k">new</span> <span class="nc">KafkaStoreFactory</span><span class="o">(</span><span class="n">props</span><span class="o">)</span>
<span class="nc">KafkaDSL</span><span class="o">.</span><span class="n">createAtLeastOnceStream</span><span class="o">(</span><span class="n">app</span><span class="o">,</span> <span class="n">sourceTopic</span><span class="o">,</span> <span class="n">checkpointStoreFactory</span><span class="o">,</span> <span class="n">props</span><span class="o">,</span> <span class="n">sourceNum</span><span class="o">)</span>
<span class="o">.</span><span class="n">writeToKafka</span><span class="o">(</span><span class="n">sinkTopic</span><span class="o">,</span> <span class="n">props</span><span class="o">,</span> <span class="n">sinkNum</span><span class="o">)</span>
<span class="o">}</span> <span class="k">else</span> <span class="o">{</span>
<span class="nc">KafkaDSL</span><span class="o">.</span><span class="n">createAtMostOnceStream</span><span class="o">(</span><span class="n">app</span><span class="o">,</span> <span class="n">sourceTopic</span><span class="o">,</span> <span class="n">props</span><span class="o">,</span> <span class="n">sourceNum</span><span class="o">)</span>
<span class="o">.</span><span class="n">writeToKafka</span><span class="o">(</span><span class="n">sinkTopic</span><span class="o">,</span> <span class="n">props</span><span class="o">,</span> <span class="n">sinkNum</span><span class="o">)</span>
<span class="o">}</span></code></pre></div>
</div>
</div>
<p>In the above example, configurations are set through Java properties and shared by <code>KafkaSource</code>, <code>KafkaSink</code> and <code>KafkaCheckpointStoreFactory</code>.
Their configurations can be defined differently as below.</p>
<h4 id="kafkasource-configurations"><code>KafkaSource</code> configurations</h4>
<table>
<thead>
<tr>
<th>Name</th>
<th>Descriptions</th>
<th>Type</th>
<th>Default</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>KafkaConfig.ZOOKEEPER_CONNECT_CONFIG</code></td>
<td>Zookeeper connect string for Kafka topics management</td>
<td>String</td>
<td>&#160;</td>
</tr>
<tr>
<td><code>KafkaConfig.CLIENT_ID_CONFIG</code></td>
<td>An id string to pass to the server when making requests</td>
<td>String</td>
<td>&#8221;&#8221;</td>
</tr>
<tr>
<td><code>KafkaConfig.GROUP_ID_CONFIG</code></td>
<td>A string that uniquely identifies a set of consumers within the same consumer group</td>
<td>&#8221;&#8221;</td>
<td>&#160;</td>
</tr>
<tr>
<td><code>KafkaConfig.FETCH_SLEEP_MS_CONFIG</code></td>
<td>The amount of time(ms) to sleep when hitting fetch.threshold</td>
<td>Int</td>
<td>100</td>
</tr>
<tr>
<td><code>KafkaConfig.FETCH_THRESHOLD_CONFIG</code></td>
<td>Size of internal queue to keep Kafka messages. Stop fetching and go to sleep when hitting the threshold</td>
<td>Int</td>
<td>10000</td>
</tr>
<tr>
<td><code>KafkaConfig.PARTITION_GROUPER_CLASS_CONFIG</code></td>
<td>Partition grouper class to group partitions amoung source tasks</td>
<td>Class</td>
<td>DefaultPartitionGrouper</td>
</tr>
<tr>
<td><code>KafkaConfig.MESSAGE_DECODER_CLASS_CONFIG</code></td>
<td>Message decoder class to decode raw bytes from Kafka</td>
<td>Class</td>
<td>DefaultMessageDecoder</td>
</tr>
<tr>
<td><code>KafkaConfig.TIMESTAMP_FILTER_CLASS_CONFIG</code></td>
<td>Timestamp filter class to filter out late messages</td>
<td>Class</td>
<td>DefaultTimeStampFilter</td>
</tr>
</tbody>
</table>
<h4 id="kafkasink-configurations"><code>KafkaSink</code> configurations</h4>
<table>
<thead>
<tr>
<th>Name</th>
<th>Descriptions</th>
<th>Type</th>
<th>Default</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>KafkaConfig.BOOTSTRAP_SERVERS_CONFIG</code></td>
<td>A list of host/port pairs to use for establishing the initial connection to the Kafka cluster</td>
<td>String</td>
<td>&#160;</td>
</tr>
<tr>
<td><code>KafkaConfig.CLIENT_ID_CONFIG</code></td>
<td>An id string to pass to the server when making requests</td>
<td>String</td>
<td>&#8221;&#8221;</td>
</tr>
</tbody>
</table>
<h4 id="kafkacheckpointstorefactory-configurations"><code>KafkaCheckpointStoreFactory</code> configurations</h4>
<table>
<thead>
<tr>
<th>Name</th>
<th>Descriptions</th>
<th>Type</th>
<th>Default</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>KafkaConfig.ZOOKEEPER_CONNECT_CONFIG</code></td>
<td>Zookeeper connect string for Kafka topics management</td>
<td>String</td>
<td>&#160;</td>
</tr>
<tr>
<td><code>KafkaConfig.BOOTSTRAP_SERVERS_CONFIG</code></td>
<td>A list of host/port pairs to use for establishing the initial connection to the Kafka cluster</td>
<td>String</td>
<td>&#160;</td>
</tr>
<tr>
<td><code>KafkaConfig.CHECKPOINT_STORE_NAME_PREFIX</code></td>
<td>Name prefix for checkpoint store</td>
<td>String</td>
<td>&#8221;&#8221;</td>
</tr>
<tr>
<td><code>KafkaConfig.REPLICATION_FACTOR</code></td>
<td>Replication factor for checkpoint store topic</td>
<td>Int</td>
<td>1</td>
</tr>
</tbody>
</table>
<h3 id="use-of-hbasesink">Use of <code>HBaseSink</code></h3>
<p>To use <code>HBaseSink</code> in your application, you first need to add the <code>gearpump-external-hbase</code> library dependency in your application:</p>
<div class="highlight"><pre><code>"org.apache.gearpump" %% "gearpump-external-hbase" % 0.8.1
</code></pre></div>
<div class="highlight"><pre><code class="language-xml"><span class="nt">&lt;dependency&gt;</span>
<span class="nt">&lt;groupId&gt;</span>org.apache.gearpump<span class="nt">&lt;/groupId&gt;</span>
<span class="nt">&lt;artifactId&gt;</span>gearpump-external-hbase<span class="nt">&lt;/artifactId&gt;</span>
<span class="nt">&lt;version&gt;</span>0.8.1<span class="nt">&lt;/version&gt;</span>
<span class="nt">&lt;/dependency&gt;</span></code></pre></div>
<p>To connect to HBase, you need to provide following info:</p>
<ul>
<li>the HBase configuration to tell which HBase service to connect</li>
<li>the table name (you must create the table yourself, see the <a href="https://hbase.apache.org/book.html">HBase documentation</a>)</li>
</ul>
<p>Then, you can use <code>HBaseSink</code> in your application:</p>
<div class="highlight"><pre><code class="language-scala"> <span class="c1">//create the HBase data sink</span>
<span class="k">val</span> <span class="n">sink</span> <span class="k">=</span> <span class="nc">HBaseSink</span><span class="o">(</span><span class="nc">UserConfig</span><span class="o">.</span><span class="n">empty</span><span class="o">,</span> <span class="n">tableName</span><span class="o">,</span> <span class="nc">HBaseConfiguration</span><span class="o">.</span><span class="n">create</span><span class="o">())</span>
<span class="c1">//create Gearpump Processor</span>
<span class="k">val</span> <span class="n">sinkProcessor</span> <span class="k">=</span> <span class="nc">DataSinkProcessor</span><span class="o">(</span><span class="n">sink</span><span class="o">,</span> <span class="n">parallelism</span><span class="o">)</span></code></pre></div>
<div class="highlight"><pre><code class="language-scala"> <span class="c1">//assume stream is a normal `Stream` in DSL</span>
<span class="n">stream</span><span class="o">.</span><span class="n">writeToHbase</span><span class="o">(</span><span class="nc">UserConfig</span><span class="o">.</span><span class="n">empty</span><span class="o">,</span> <span class="n">tableName</span><span class="o">,</span> <span class="n">parallelism</span><span class="o">,</span> <span class="s">&quot;write to HBase&quot;</span><span class="o">)</span></code></pre></div>
<p>You can tune the connection to HBase via the HBase configuration passed in. If not passed, Gearpump will try to check local classpath to find a valid HBase configuration (<code>hbase-site.xml</code>).</p>
<p>Attention, due to the issue discussed <a href="http://stackoverflow.com/questions/24456484/hbase-managed-zookeeper-suddenly-trying-to-connect-to-localhost-instead-of-zooke">here</a> you may need to create additional configuration for your HBase sink:</p>
<div class="highlight"><pre><code class="language-scala"> <span class="k">def</span> <span class="n">hadoopConfig</span> <span class="k">=</span> <span class="o">{</span>
<span class="k">val</span> <span class="n">conf</span> <span class="k">=</span> <span class="k">new</span> <span class="nc">Configuration</span><span class="o">()</span>
<span class="n">conf</span><span class="o">.</span><span class="n">set</span><span class="o">(</span><span class="s">&quot;hbase.zookeeper.quorum&quot;</span><span class="o">,</span> <span class="s">&quot;zookeeperHost&quot;</span><span class="o">)</span>
<span class="n">conf</span><span class="o">.</span><span class="n">set</span><span class="o">(</span><span class="s">&quot;hbase.zookeeper.property.clientPort&quot;</span><span class="o">,</span> <span class="s">&quot;2181&quot;</span><span class="o">)</span>
<span class="n">conf</span>
<span class="o">}</span></code></pre></div>
<div class="highlight"><pre><code class="language-scala"> <span class="k">val</span> <span class="n">sink</span> <span class="k">=</span> <span class="nc">HBaseSink</span><span class="o">(</span><span class="nc">UserConfig</span><span class="o">.</span><span class="n">empty</span><span class="o">,</span> <span class="n">tableName</span><span class="o">,</span> <span class="n">hadoopConfig</span><span class="o">)</span></code></pre></div>
<h2 id="how-to-implement-your-own-datasource">How to implement your own <code>DataSource</code></h2>
<p>To implement your own <code>DataSource</code>, you need to implement two things:</p>
<ol>
<li>The data source itself</li>
<li>a helper class to easy the usage in a DSL</li>
</ol>
<h3 id="implement-your-own-datasource">Implement your own <code>DataSource</code></h3>
<p>You need to implement a class derived from <code>org.apache.gearpump.streaming.transaction.api.TimeReplayableSource</code>.</p>
<h3 id="implement-dsl-helper-optional">Implement DSL helper (Optional)</h3>
<p>If you would like to have a DSL at hand you may start with this customized stream; it is better if you can implement your own DSL helper.
You can refer <code>KafkaDSLUtil</code> as an example in Gearpump source.</p>
<p>Below is some code snippet from <code>KafkaDSLUtil</code>:</p>
<div class="highlight"><pre><code class="language-scala"><span class="k">object</span> <span class="nc">KafkaDSLUtil</span> <span class="o">{</span>
<span class="k">def</span> <span class="n">createStream</span><span class="o">[</span><span class="kt">T</span><span class="o">](</span>
<span class="n">app</span><span class="k">:</span> <span class="kt">StreamApp</span><span class="o">,</span>
<span class="n">topics</span><span class="k">:</span> <span class="kt">String</span><span class="o">,</span>
<span class="n">parallelism</span><span class="k">:</span> <span class="kt">Int</span><span class="o">,</span>
<span class="n">description</span><span class="k">:</span> <span class="kt">String</span><span class="o">,</span>
<span class="n">properties</span><span class="k">:</span> <span class="kt">Properties</span><span class="o">)</span><span class="k">:</span> <span class="kt">dsl.Stream</span><span class="o">[</span><span class="kt">T</span><span class="o">]</span> <span class="k">=</span> <span class="o">{</span>
<span class="n">app</span><span class="o">.</span><span class="n">source</span><span class="o">[</span><span class="kt">T</span><span class="o">](</span><span class="k">new</span> <span class="nc">KafkaSource</span><span class="o">(</span><span class="n">topics</span><span class="o">,</span> <span class="n">properties</span><span class="o">),</span> <span class="n">parallelism</span><span class="o">,</span> <span class="n">description</span><span class="o">)</span>
<span class="o">}</span>
<span class="o">}</span></code></pre></div>
<h2 id="how-to-implement-your-own-datasink">How to implement your own <code>DataSink</code></h2>
<p>To implement your own <code>DataSink</code>, you need to implement two things:</p>
<ol>
<li>The data sink itself</li>
<li>a helper class to make it easy use in DSL</li>
</ol>
<h3 id="implement-your-own-datasink">Implement your own <code>DataSink</code></h3>
<p>You need to implement a class derived from <code>org.apache.gearpump.streaming.sink.DataSink</code>.</p>
<h3 id="implement-dsl-helper-optional-1">Implement DSL helper (Optional)</h3>
<p>If you would like to have a DSL at hand you may start with this customized stream; it is better if you can implement your own DSL helper.
You can refer <code>HBaseDSLSink</code> as an example in Gearpump source.</p>
<p>Below is some code snippet from <code>HBaseDSLSink</code>:</p>
<div class="highlight"><pre><code class="language-scala"><span class="k">class</span> <span class="nc">HBaseDSLSink</span><span class="o">[</span><span class="kt">T</span><span class="o">](</span><span class="n">stream</span><span class="k">:</span> <span class="kt">Stream</span><span class="o">[</span><span class="kt">T</span><span class="o">])</span> <span class="o">{</span>
<span class="k">def</span> <span class="n">writeToHbase</span><span class="o">(</span><span class="n">userConfig</span><span class="k">:</span> <span class="kt">UserConfig</span><span class="o">,</span> <span class="n">table</span><span class="k">:</span> <span class="kt">String</span><span class="o">,</span> <span class="n">parallism</span><span class="k">:</span> <span class="kt">Int</span><span class="o">,</span> <span class="n">description</span><span class="k">:</span> <span class="kt">String</span><span class="o">)</span><span class="k">:</span> <span class="kt">Stream</span><span class="o">[</span><span class="kt">T</span><span class="o">]</span> <span class="k">=</span> <span class="o">{</span>
<span class="n">stream</span><span class="o">.</span><span class="n">sink</span><span class="o">(</span><span class="nc">HBaseSink</span><span class="o">[</span><span class="kt">T</span><span class="o">](</span><span class="n">userConfig</span><span class="o">,</span> <span class="n">table</span><span class="o">),</span> <span class="n">parallism</span><span class="o">,</span> <span class="n">userConfig</span><span class="o">,</span> <span class="n">description</span><span class="o">)</span>
<span class="o">}</span>
<span class="k">def</span> <span class="n">writeToHbase</span><span class="o">(</span><span class="n">userConfig</span><span class="k">:</span> <span class="kt">UserConfig</span><span class="o">,</span> <span class="n">configuration</span><span class="k">:</span> <span class="kt">Configuration</span><span class="o">,</span> <span class="n">table</span><span class="k">:</span> <span class="kt">String</span><span class="o">,</span> <span class="n">parallism</span><span class="k">:</span> <span class="kt">Int</span><span class="o">,</span> <span class="n">description</span><span class="k">:</span> <span class="kt">String</span><span class="o">)</span><span class="k">:</span> <span class="kt">Stream</span><span class="o">[</span><span class="kt">T</span><span class="o">]</span> <span class="k">=</span> <span class="o">{</span>
<span class="n">stream</span><span class="o">.</span><span class="n">sink</span><span class="o">(</span><span class="nc">HBaseSink</span><span class="o">[</span><span class="kt">T</span><span class="o">](</span><span class="n">userConfig</span><span class="o">,</span> <span class="n">table</span><span class="o">,</span> <span class="n">configuration</span><span class="o">),</span> <span class="n">parallism</span><span class="o">,</span> <span class="n">userConfig</span><span class="o">,</span> <span class="n">description</span><span class="o">)</span>
<span class="o">}</span>
<span class="o">}</span>
<span class="k">object</span> <span class="nc">HBaseDSLSink</span> <span class="o">{</span>
<span class="k">implicit</span> <span class="k">def</span> <span class="n">streamToHBaseDSLSink</span><span class="o">[</span><span class="kt">T</span><span class="o">](</span><span class="n">stream</span><span class="k">:</span> <span class="kt">Stream</span><span class="o">[</span><span class="kt">T</span><span class="o">])</span><span class="k">:</span> <span class="kt">HBaseDSLSink</span><span class="o">[</span><span class="kt">T</span><span class="o">]</span> <span class="k">=</span> <span class="o">{</span>
<span class="k">new</span> <span class="nc">HBaseDSLSink</span><span class="o">[</span><span class="kt">T</span><span class="o">](</span><span class="n">stream</span><span class="o">)</span>
<span class="o">}</span>
<span class="o">}</span></code></pre></div>
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