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<h1 title="Package" class="title">Package&nbsp;org.apache.hadoop.mapred.lib</h1>
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<table class="typeSummary" border="0" cellpadding="3" cellspacing="0" summary="Class Summary table, listing classes, and an explanation">
<caption><span>Class Summary</span><span class="tabEnd">&nbsp;</span></caption>
<tr>
<th class="colFirst" scope="col">Class</th>
<th class="colLast" scope="col">Description</th>
</tr>
<tbody>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/BinaryPartitioner.html" title="class in org.apache.hadoop.mapred.lib">BinaryPartitioner</a>&lt;V&gt;</td>
<td class="colLast">
<div class="block">Partition <a href="../../../../../org/apache/hadoop/io/BinaryComparable.html" title="class in org.apache.hadoop.io"><code>BinaryComparable</code></a> keys using a configurable part of
the bytes array returned by <a href="../../../../../org/apache/hadoop/io/BinaryComparable.html#getBytes--"><code>BinaryComparable.getBytes()</code></a>.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/ChainMapper.html" title="class in org.apache.hadoop.mapred.lib">ChainMapper</a></td>
<td class="colLast">
<div class="block">The ChainMapper class allows to use multiple Mapper classes within a single
Map task.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/ChainReducer.html" title="class in org.apache.hadoop.mapred.lib">ChainReducer</a></td>
<td class="colLast">
<div class="block">The ChainReducer class allows to chain multiple Mapper classes after a
Reducer within the Reducer task.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/CombineFileInputFormat.html" title="class in org.apache.hadoop.mapred.lib">CombineFileInputFormat</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">An abstract <a href="../../../../../org/apache/hadoop/mapred/InputFormat.html" title="interface in org.apache.hadoop.mapred"><code>InputFormat</code></a> that returns <a href="../../../../../org/apache/hadoop/mapred/lib/CombineFileSplit.html" title="class in org.apache.hadoop.mapred.lib"><code>CombineFileSplit</code></a>'s
in <a href="../../../../../org/apache/hadoop/mapred/InputFormat.html#getSplits-org.apache.hadoop.mapred.JobConf-int-"><code>InputFormat.getSplits(JobConf, int)</code></a> method.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/CombineFileRecordReader.html" title="class in org.apache.hadoop.mapred.lib">CombineFileRecordReader</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">A generic RecordReader that can hand out different recordReaders
for each chunk in a <a href="../../../../../org/apache/hadoop/mapred/lib/CombineFileSplit.html" title="class in org.apache.hadoop.mapred.lib"><code>CombineFileSplit</code></a>.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/CombineFileRecordReaderWrapper.html" title="class in org.apache.hadoop.mapred.lib">CombineFileRecordReaderWrapper</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">A wrapper class for a record reader that handles a single file split.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/CombineFileSplit.html" title="class in org.apache.hadoop.mapred.lib">CombineFileSplit</a></td>
<td class="colLast">&nbsp;</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/CombineSequenceFileInputFormat.html" title="class in org.apache.hadoop.mapred.lib">CombineSequenceFileInputFormat</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">Input format that is a <code>CombineFileInputFormat</code>-equivalent for
<code>SequenceFileInputFormat</code>.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/CombineTextInputFormat.html" title="class in org.apache.hadoop.mapred.lib">CombineTextInputFormat</a></td>
<td class="colLast">
<div class="block">Input format that is a <code>CombineFileInputFormat</code>-equivalent for
<code>TextInputFormat</code>.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/FieldSelectionMapReduce.html" title="class in org.apache.hadoop.mapred.lib">FieldSelectionMapReduce</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">This class implements a mapper/reducer class that can be used to perform
field selections in a manner similar to unix cut.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/FilterOutputFormat.html" title="class in org.apache.hadoop.mapred.lib">FilterOutputFormat</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">FilterOutputFormat is a convenience class that wraps OutputFormat.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/HashPartitioner.html" title="class in org.apache.hadoop.mapred.lib">HashPartitioner</a>&lt;K2,V2&gt;</td>
<td class="colLast">
<div class="block">Partition keys by their <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html?is-external=true#hashCode--" title="class or interface in java.lang"><code>Object.hashCode()</code></a>.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/IdentityMapper.html" title="class in org.apache.hadoop.mapred.lib">IdentityMapper</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">Implements the identity function, mapping inputs directly to outputs.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/IdentityReducer.html" title="class in org.apache.hadoop.mapred.lib">IdentityReducer</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">Performs no reduction, writing all input values directly to the output.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/InputSampler.html" title="class in org.apache.hadoop.mapred.lib">InputSampler</a>&lt;K,V&gt;</td>
<td class="colLast">&nbsp;</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/InverseMapper.html" title="class in org.apache.hadoop.mapred.lib">InverseMapper</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">A <a href="../../../../../org/apache/hadoop/mapred/Mapper.html" title="interface in org.apache.hadoop.mapred"><code>Mapper</code></a> that swaps keys and values.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/KeyFieldBasedComparator.html" title="class in org.apache.hadoop.mapred.lib">KeyFieldBasedComparator</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">This comparator implementation provides a subset of the features provided
by the Unix/GNU Sort.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/KeyFieldBasedPartitioner.html" title="class in org.apache.hadoop.mapred.lib">KeyFieldBasedPartitioner</a>&lt;K2,V2&gt;</td>
<td class="colLast">
<div class="block">Defines a way to partition keys based on certain key fields (also see
<a href="../../../../../org/apache/hadoop/mapred/lib/KeyFieldBasedComparator.html" title="class in org.apache.hadoop.mapred.lib"><code>KeyFieldBasedComparator</code></a>.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/LazyOutputFormat.html" title="class in org.apache.hadoop.mapred.lib">LazyOutputFormat</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">A Convenience class that creates output lazily.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/LongSumReducer.html" title="class in org.apache.hadoop.mapred.lib">LongSumReducer</a>&lt;K&gt;</td>
<td class="colLast">
<div class="block">A <a href="../../../../../org/apache/hadoop/mapred/Reducer.html" title="interface in org.apache.hadoop.mapred"><code>Reducer</code></a> that sums long values.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/MultipleInputs.html" title="class in org.apache.hadoop.mapred.lib">MultipleInputs</a></td>
<td class="colLast">
<div class="block">This class supports MapReduce jobs that have multiple input paths with
a different <a href="../../../../../org/apache/hadoop/mapred/InputFormat.html" title="interface in org.apache.hadoop.mapred"><code>InputFormat</code></a> and <a href="../../../../../org/apache/hadoop/mapred/Mapper.html" title="interface in org.apache.hadoop.mapred"><code>Mapper</code></a> for each path</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/MultipleOutputFormat.html" title="class in org.apache.hadoop.mapred.lib">MultipleOutputFormat</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">This abstract class extends the FileOutputFormat, allowing to write the
output data to different output files.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/MultipleOutputs.html" title="class in org.apache.hadoop.mapred.lib">MultipleOutputs</a></td>
<td class="colLast">
<div class="block">The MultipleOutputs class simplifies writing to additional outputs other
than the job default output via the <code>OutputCollector</code> passed to
the <code>map()</code> and <code>reduce()</code> methods of the
<code>Mapper</code> and <code>Reducer</code> implementations.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/MultipleSequenceFileOutputFormat.html" title="class in org.apache.hadoop.mapred.lib">MultipleSequenceFileOutputFormat</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">This class extends the MultipleOutputFormat, allowing to write the output data
to different output files in sequence file output format.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/MultipleTextOutputFormat.html" title="class in org.apache.hadoop.mapred.lib">MultipleTextOutputFormat</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">This class extends the MultipleOutputFormat, allowing to write the output
data to different output files in Text output format.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/MultithreadedMapRunner.html" title="class in org.apache.hadoop.mapred.lib">MultithreadedMapRunner</a>&lt;K1,V1,K2,V2&gt;</td>
<td class="colLast">
<div class="block">Multithreaded implementation for <a href="../../../../../org/apache/hadoop/mapred/MapRunnable.html" title="interface in org.apache.hadoop.mapred"><code>MapRunnable</code></a>.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/NLineInputFormat.html" title="class in org.apache.hadoop.mapred.lib">NLineInputFormat</a></td>
<td class="colLast">
<div class="block">NLineInputFormat which splits N lines of input as one split.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/NullOutputFormat.html" title="class in org.apache.hadoop.mapred.lib">NullOutputFormat</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">Consume all outputs and put them in /dev/null.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/RegexMapper.html" title="class in org.apache.hadoop.mapred.lib">RegexMapper</a>&lt;K&gt;</td>
<td class="colLast">
<div class="block">A <a href="../../../../../org/apache/hadoop/mapred/Mapper.html" title="interface in org.apache.hadoop.mapred"><code>Mapper</code></a> that extracts text matching a regular expression.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/TokenCountMapper.html" title="class in org.apache.hadoop.mapred.lib">TokenCountMapper</a>&lt;K&gt;</td>
<td class="colLast">
<div class="block">A <a href="../../../../../org/apache/hadoop/mapred/Mapper.html" title="interface in org.apache.hadoop.mapred"><code>Mapper</code></a> that maps text values into &lt;token,freq&gt; pairs.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><a href="../../../../../org/apache/hadoop/mapred/lib/TotalOrderPartitioner.html" title="class in org.apache.hadoop.mapred.lib">TotalOrderPartitioner</a>&lt;K,V&gt;</td>
<td class="colLast">
<div class="block">Partitioner effecting a total order by reading split points from
an externally generated source.</div>
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