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<div class="subTitle">org.apache.hadoop.mapreduce.lib.aggregate</div>
<h2 title="Class ValueAggregatorReducer" class="title">Class ValueAggregatorReducer&lt;K1 extends <a href="../../../../../../org/apache/hadoop/io/WritableComparable.html" title="interface in org.apache.hadoop.io">WritableComparable</a>&lt;?&gt;,V1 extends <a href="../../../../../../org/apache/hadoop/io/Writable.html" title="interface in org.apache.hadoop.io">Writable</a>&gt;</h2>
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<li><a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html" title="class in org.apache.hadoop.mapreduce">org.apache.hadoop.mapreduce.Reducer</a>&lt;<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>&gt;</li>
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<li>org.apache.hadoop.mapreduce.lib.aggregate.ValueAggregatorReducer&lt;K1,V1&gt;</li>
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<pre>@InterfaceAudience.Public
@InterfaceStability.Stable
public class <span class="typeNameLabel">ValueAggregatorReducer&lt;K1 extends <a href="../../../../../../org/apache/hadoop/io/WritableComparable.html" title="interface in org.apache.hadoop.io">WritableComparable</a>&lt;?&gt;,V1 extends <a href="../../../../../../org/apache/hadoop/io/Writable.html" title="interface in org.apache.hadoop.io">Writable</a>&gt;</span>
extends <a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html" title="class in org.apache.hadoop.mapreduce">Reducer</a>&lt;<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>&gt;</pre>
<div class="block">This class implements the generic reducer of Aggregate.</div>
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<td class="colOne"><code><span class="memberNameLink"><a href="../../../../../../org/apache/hadoop/mapreduce/lib/aggregate/ValueAggregatorReducer.html#ValueAggregatorReducer--">ValueAggregatorReducer</a></span>()</code>&nbsp;</td>
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<td class="colFirst"><code>void</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../../../../org/apache/hadoop/mapreduce/lib/aggregate/ValueAggregatorReducer.html#reduce-org.apache.hadoop.io.Text-java.lang.Iterable-org.apache.hadoop.mapreduce.Reducer.Context-">reduce</a></span>(<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>&nbsp;key,
<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>&lt;<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>&gt;&nbsp;values,
org.apache.hadoop.mapreduce.Reducer.Context&nbsp;context)</code>
<div class="block">This method is called once for each key.</div>
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<td class="colFirst"><code>void</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../../../../org/apache/hadoop/mapreduce/lib/aggregate/ValueAggregatorReducer.html#setup-org.apache.hadoop.mapreduce.Reducer.Context-">setup</a></span>(org.apache.hadoop.mapreduce.Reducer.Context&nbsp;context)</code>
<div class="block">Called once at the start of the task.</div>
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<h3>Methods inherited from class&nbsp;org.apache.hadoop.mapreduce.<a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html" title="class in org.apache.hadoop.mapreduce">Reducer</a></h3>
<code><a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html#cleanup-org.apache.hadoop.mapreduce.Reducer.Context-">cleanup</a>, <a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html#run-org.apache.hadoop.mapreduce.Reducer.Context-">run</a></code></li>
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<h4>ValueAggregatorReducer</h4>
<pre>public&nbsp;ValueAggregatorReducer()</pre>
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<h4>setup</h4>
<pre>public&nbsp;void&nbsp;setup(org.apache.hadoop.mapreduce.Reducer.Context&nbsp;context)
throws <a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a>,
<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/InterruptedException.html?is-external=true" title="class or interface in java.lang">InterruptedException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from class:&nbsp;<code><a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html#setup-org.apache.hadoop.mapreduce.Reducer.Context-">Reducer</a></code></span></div>
<div class="block">Called once at the start of the task.</div>
<dl>
<dt><span class="overrideSpecifyLabel">Overrides:</span></dt>
<dd><code><a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html#setup-org.apache.hadoop.mapreduce.Reducer.Context-">setup</a></code>&nbsp;in class&nbsp;<code><a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html" title="class in org.apache.hadoop.mapreduce">Reducer</a>&lt;<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>&gt;</code></dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a></code></dd>
<dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/InterruptedException.html?is-external=true" title="class or interface in java.lang">InterruptedException</a></code></dd>
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<h4>reduce</h4>
<pre>public&nbsp;void&nbsp;reduce(<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>&nbsp;key,
<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>&lt;<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>&gt;&nbsp;values,
org.apache.hadoop.mapreduce.Reducer.Context&nbsp;context)
throws <a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a>,
<a href="https://docs.oracle.com/javase/8/docs/api/java/lang/InterruptedException.html?is-external=true" title="class or interface in java.lang">InterruptedException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from class:&nbsp;<code><a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html#reduce-KEYIN-java.lang.Iterable-org.apache.hadoop.mapreduce.Reducer.Context-">Reducer</a></code></span></div>
<div class="block">This method is called once for each key. Most applications will define
their reduce class by overriding this method. The default implementation
is an identity function.</div>
<dl>
<dt><span class="overrideSpecifyLabel">Overrides:</span></dt>
<dd><code><a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html#reduce-KEYIN-java.lang.Iterable-org.apache.hadoop.mapreduce.Reducer.Context-">reduce</a></code>&nbsp;in class&nbsp;<code><a href="../../../../../../org/apache/hadoop/mapreduce/Reducer.html" title="class in org.apache.hadoop.mapreduce">Reducer</a>&lt;<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>,<a href="../../../../../../org/apache/hadoop/io/Text.html" title="class in org.apache.hadoop.io">Text</a>&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>key</code> - the key is expected to be a Text object, whose prefix indicates
the type of aggregation to aggregate the values. In effect, data
driven computing is achieved. It is assumed that each aggregator's
getReport method emits appropriate output for the aggregator. This
may be further customized.</dd>
<dd><code>values</code> - the values to be aggregated</dd>
<dd><code>context</code> - </dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a></code></dd>
<dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/InterruptedException.html?is-external=true" title="class or interface in java.lang">InterruptedException</a></code></dd>
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