zzg/pj2
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
master
pj2/doc/edu/rit/pjmr/ReducerTask.html
T
Zack Zatkin-Gold c2c773e0c3 initial revision
2016-04-27 01:07:35 -04:00

348 lines
19 KiB
HTML
Raw Permalink Blame History

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<!-- NewPage -->
<html lang="en">
<head>
<!-- Generated by javadoc (version 1.7.0_51) on Wed Apr 06 13:11:06 EDT 2016 -->
<title>ReducerTask (Parallel Java 2 Library Documentation)</title>
<meta name="date" content="2016-04-06">
<link rel="stylesheet" type="text/css" href="../../../stylesheet.css" title="Style">
</head>
<body>
<script type="text/javascript"><!--
if (location.href.indexOf('is-external=true') == -1) {
parent.document.title="ReducerTask (Parallel Java 2 Library Documentation)";
}
//-->
</script>
<noscript>
<div>JavaScript is disabled on your browser.</div>
</noscript>
<!-- ========= START OF TOP NAVBAR ======= -->
<div class="topNav"><a name="navbar_top">
<!-- -->
</a><a href="#skip-navbar_top" title="Skip navigation links"></a><a name="navbar_top_firstrow">
<!-- -->
</a>
<ul class="navList" title="Navigation">
<li><a href="../../../overview-summary.html">Overview</a></li>
<li><a href="package-summary.html">Package</a></li>
<li class="navBarCell1Rev">Class</li>
<li><a href="class-use/ReducerTask.html">Use</a></li>
<li><a href="package-tree.html">Tree</a></li>
<li><a href="../../../deprecated-list.html">Deprecated</a></li>
<li><a href="../../../index-files/index-1.html">Index</a></li>
<li><a href="../../../help-doc.html">Help</a></li>
</ul>
</div>
<div class="subNav">
<ul class="navList">
<li><a href="../../../edu/rit/pjmr/ReducerConfig.html" title="class in edu.rit.pjmr"><span class="strong">Prev Class</span></a></li>
<li><a href="../../../edu/rit/pjmr/ReducerTaskConfig.html" title="class in edu.rit.pjmr"><span class="strong">Next Class</span></a></li>
</ul>
<ul class="navList">
<li><a href="../../../index.html?edu/rit/pjmr/ReducerTask.html" target="_top">Frames</a></li>
<li><a href="ReducerTask.html" target="_top">No Frames</a></li>
</ul>
<ul class="navList" id="allclasses_navbar_top">
<li><a href="../../../allclasses-noframe.html">All Classes</a></li>
</ul>
<div>
<script type="text/javascript"><!--
allClassesLink = document.getElementById("allclasses_navbar_top");
if(window==top) {
allClassesLink.style.display = "block";
}
else {
allClassesLink.style.display = "none";
}
//-->
</script>
</div>
<div>
<ul class="subNavList">
<li>Summary:&nbsp;</li>
<li>Nested&nbsp;|&nbsp;</li>
<li><a href="#fields_inherited_from_class_edu.rit.pj2.Task">Field</a>&nbsp;|&nbsp;</li>
<li><a href="#constructor_summary">Constr</a>&nbsp;|&nbsp;</li>
<li><a href="#method_summary">Method</a></li>
</ul>
<ul class="subNavList">
<li>Detail:&nbsp;</li>
<li>Field&nbsp;|&nbsp;</li>
<li><a href="#constructor_detail">Constr</a>&nbsp;|&nbsp;</li>
<li><a href="#method_detail">Method</a></li>
</ul>
</div>
<a name="skip-navbar_top">
<!-- -->
</a></div>
<!-- ========= END OF TOP NAVBAR ========= -->
<!-- ======== START OF CLASS DATA ======== -->
<div class="header">
<div class="subTitle">edu.rit.pjmr</div>
<h2 title="Class ReducerTask" class="title">Class ReducerTask&lt;K,V extends <a href="../../../edu/rit/pj2/Vbl.html" title="interface in edu.rit.pj2">Vbl</a>&gt;</h2>
</div>
<div class="contentContainer">
<ul class="inheritance">
<li><a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">java.lang.Object</a></li>
<li>
<ul class="inheritance">
<li><a href="../../../edu/rit/pj2/Task.html" title="class in edu.rit.pj2">edu.rit.pj2.Task</a></li>
<li>
<ul class="inheritance">
<li>edu.rit.pjmr.ReducerTask&lt;K,V&gt;</li>
</ul>
</li>
</ul>
</li>
</ul>
<div class="description">
<ul class="blockList">
<li class="blockList">
<dl><dt><span class="strong">Type Parameters:</span></dt><dd><code>K</code> - Mapper output key data type.</dd><dd><code>V</code> - Mapper output value data type; must implement interface
<a href="../../../edu/rit/pj2/Vbl.html" title="interface in edu.rit.pj2">Vbl</a>.</dd></dl>
<hr>
<br>
<pre>public class <span class="strong">ReducerTask&lt;K,V extends <a href="../../../edu/rit/pj2/Vbl.html" title="interface in edu.rit.pj2">Vbl</a>&gt;</span>
extends <a href="../../../edu/rit/pj2/Task.html" title="class in edu.rit.pj2">Task</a></pre>
<div class="block">Class ReducerTask provides a reducer task in the Parallel Java Map Reduce
Framework. Do not create reducer tasks directly; rather, define reducer tasks
as part of a <a href="../../../edu/rit/pjmr/PjmrJob.html" title="class in edu.rit.pjmr">PjmrJob</a>.
<P>
Each reducer task in a PJMR job does the following, using the configuration
specified in the PJMR job. For further information, refer to the
documentation for the classes mentioned below.
<OL TYPE=1>
<P><LI>
For each of the reducer task's configured <a href="../../../edu/rit/pjmr/Reducer.html" title="class in edu.rit.pjmr">Reducer</a>s, create the
reducer object.
<P><LI>
Create the reducer task's configured <a href="../../../edu/rit/pjmr/Combiner.html" title="class in edu.rit.pjmr">Combiner</a>.
<P><LI>
If the reducer task was configured with a <a href="../../../edu/rit/pjmr/Customizer.html" title="class in edu.rit.pjmr">Customizer</a>, create the
customizer object and call its <TT>start()</TT> method, passing in any
configured argument strings plus the combiner.
<P><LI>
Receive a combiner object from each <a href="../../../edu/rit/pjmr/MapperTask.html" title="class in edu.rit.pjmr">MapperTask</a>. Reduce all the
received combiner objects together into the reducer task's combiner.
<P><LI>
If the reducer task was configured with a customizer and the customizer's
<TT>comesBefore()</TT> method was overridden, sort the combiner's (key,
value) pairs into the order determined by the <TT>comesBefore()</TT> method.
Otherwise, leave the combiner's (key, value) pairs in an unspecified order.
<P><LI>
Do a parallel loop over the (key, value) pairs in the combiner. Each parallel
loop iteration processes one (key, value) pair. There is one parallel team
thread for each reducer. The reducer task's <TT>schedule</TT> and
<TT>chunk</TT> properties determine how the parallel loop iterations are
partitioned among the parallel team threads; that is, how the (key, value)
pairs are partitioned among the reducers. Each parallel team thread does the
following:
<OL TYPE=a>
<P><LI>
Call the reducer's <TT>start()</TT> method, passing in any configured
argument strings.
<P><LI>
Repeatedly call the reducer's <TT>reduce()</TT> method, passing in one of the
combiner's (key, value) pairs.
<P><LI>
When there are no more pairs, call the reducer's <TT>finish()</TT> method.
</OL>
<P><LI>
After all the parallel team threads have finished, if the reducer task was
configured with a customizer, call the customizer's <TT>finish()</TT> method,
passing in the combiner.
</OL></div>
</li>
</ul>
</div>
<div class="summary">
<ul class="blockList">
<li class="blockList">
<!-- =========== FIELD SUMMARY =========== -->
<ul class="blockList">
<li class="blockList"><a name="field_summary">
<!-- -->
</a>
<h3>Field Summary</h3>
<ul class="blockList">
<li class="blockList"><a name="fields_inherited_from_class_edu.rit.pj2.Task">
<!-- -->
</a>
<h3>Fields inherited from class&nbsp;edu.rit.pj2.<a href="../../../edu/rit/pj2/Task.html" title="class in edu.rit.pj2">Task</a></h3>
<code><a href="../../../edu/rit/pj2/Task.html#ALL_CORES">ALL_CORES</a>, <a href="../../../edu/rit/pj2/Task.html#ALL_GPUS">ALL_GPUS</a>, <a href="../../../edu/rit/pj2/Task.html#ANY_NODE_NAME">ANY_NODE_NAME</a>, <a href="../../../edu/rit/pj2/Task.html#DEFAULT_CHUNK">DEFAULT_CHUNK</a>, <a href="../../../edu/rit/pj2/Task.html#DEFAULT_CORES">DEFAULT_CORES</a>, <a href="../../../edu/rit/pj2/Task.html#DEFAULT_GPUS">DEFAULT_GPUS</a>, <a href="../../../edu/rit/pj2/Task.html#DEFAULT_NODE_NAME">DEFAULT_NODE_NAME</a>, <a href="../../../edu/rit/pj2/Task.html#DEFAULT_SCHEDULE">DEFAULT_SCHEDULE</a>, <a href="../../../edu/rit/pj2/Task.html#DEFAULT_THREADS">DEFAULT_THREADS</a>, <a href="../../../edu/rit/pj2/Task.html#dynamic">dynamic</a>, <a href="../../../edu/rit/pj2/Task.html#fixed">fixed</a>, <a href="../../../edu/rit/pj2/Task.html#guided">guided</a>, <a href="../../../edu/rit/pj2/Task.html#leapfrog">leapfrog</a>, <a href="../../../edu/rit/pj2/Task.html#proportional">proportional</a>, <a href="../../../edu/rit/pj2/Task.html#STANDARD_CHUNK">STANDARD_CHUNK</a>, <a href="../../../edu/rit/pj2/Task.html#THREADS_EQUALS_CORES">THREADS_EQUALS_CORES</a></code></li>
</ul>
</li>
</ul>
<!-- ======== CONSTRUCTOR SUMMARY ======== -->
<ul class="blockList">
<li class="blockList"><a name="constructor_summary">
<!-- -->
</a>
<h3>Constructor Summary</h3>
<table class="overviewSummary" border="0" cellpadding="3" cellspacing="0" summary="Constructor Summary table, listing constructors, and an explanation">
<caption><span>Constructors</span><span class="tabEnd">&nbsp;</span></caption>
<tr>
<th class="colOne" scope="col">Constructor and Description</th>
</tr>
<tr class="altColor">
<td class="colOne"><code><strong><a href="../../../edu/rit/pjmr/ReducerTask.html#ReducerTask()">ReducerTask</a></strong>()</code>&nbsp;</td>
</tr>
</table>
</li>
</ul>
<!-- ========== METHOD SUMMARY =========== -->
<ul class="blockList">
<li class="blockList"><a name="method_summary">
<!-- -->
</a>
<h3>Method Summary</h3>
<table class="overviewSummary" border="0" cellpadding="3" cellspacing="0" summary="Method Summary table, listing methods, and an explanation">
<caption><span>Methods</span><span class="tabEnd">&nbsp;</span></caption>
<tr>
<th class="colFirst" scope="col">Modifier and Type</th>
<th class="colLast" scope="col">Method and Description</th>
</tr>
<tr class="altColor">
<td class="colFirst"><code>void</code></td>
<td class="colLast"><code><strong><a href="../../../edu/rit/pjmr/ReducerTask.html#main(java.lang.String[])">main</a></strong>(<a href="http://docs.oracle.com/javase/7/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>[]&nbsp;args)</code>
<div class="block">Reducer task main program.</div>
</td>
</tr>
</table>
<ul class="blockList">
<li class="blockList"><a name="methods_inherited_from_class_edu.rit.pj2.Task">
<!-- -->
</a>
<h3>Methods inherited from class&nbsp;edu.rit.pj2.<a href="../../../edu/rit/pj2/Task.html" title="class in edu.rit.pj2">Task</a></h3>
<code><a href="../../../edu/rit/pj2/Task.html#actualThreads()">actualThreads</a>, <a href="../../../edu/rit/pj2/Task.html#addTupleListener(edu.rit.pj2.TupleListener)">addTupleListener</a>, <a href="../../../edu/rit/pj2/Task.html#chunk()">chunk</a>, <a href="../../../edu/rit/pj2/Task.html#chunk(int)">chunk</a>, <a href="../../../edu/rit/pj2/Task.html#cores()">cores</a>, <a href="../../../edu/rit/pj2/Task.html#cores(int)">cores</a>, <a href="../../../edu/rit/pj2/Task.html#coresRequired()">coresRequired</a>, <a href="../../../edu/rit/pj2/Task.html#getMatchingTuple(int)">getMatchingTuple</a>, <a href="../../../edu/rit/pj2/Task.html#gpus()">gpus</a>, <a href="../../../edu/rit/pj2/Task.html#gpus(int)">gpus</a>, <a href="../../../edu/rit/pj2/Task.html#gpusRequired()">gpusRequired</a>, <a href="../../../edu/rit/pj2/Task.html#groupSize()">groupSize</a>, <a href="../../../edu/rit/pj2/Task.html#initialChunk()">initialChunk</a>, <a href="../../../edu/rit/pj2/Task.html#initialSchedule()">initialSchedule</a>, <a href="../../../edu/rit/pj2/Task.html#initialThreads()">initialThreads</a>, <a href="../../../edu/rit/pj2/Task.html#matchingTupleCount()">matchingTupleCount</a>, <a href="../../../edu/rit/pj2/Task.html#nodeName()">nodeName</a>, <a href="../../../edu/rit/pj2/Task.html#nodeName(java.lang.String)">nodeName</a>, <a href="../../../edu/rit/pj2/Task.html#nodeNameRequired()">nodeNameRequired</a>, <a href="../../../edu/rit/pj2/Task.html#parallelDo(int, edu.rit.pj2.Section)">parallelDo</a>, <a href="../../../edu/rit/pj2/Task.html#parallelDo(edu.rit.pj2.Section...)">parallelDo</a>, <a href="../../../edu/rit/pj2/Task.html#parallelFor(int, int)">parallelFor</a>, <a href="../../../edu/rit/pj2/Task.html#parallelFor(long, long)">parallelFor</a>, <a href="../../../edu/rit/pj2/Task.html#parallelFor(edu.rit.pj2.WorkQueue)">parallelFor</a>, <a href="../../../edu/rit/pj2/Task.html#putTuple(int, edu.rit.pj2.Tuple)">putTuple</a>, <a href="../../../edu/rit/pj2/Task.html#putTuple(edu.rit.pj2.Tuple)">putTuple</a>, <a href="../../../edu/rit/pj2/Task.html#readTuple(T)">readTuple</a>, <a href="../../../edu/rit/pj2/Task.html#schedule()">schedule</a>, <a href="../../../edu/rit/pj2/Task.html#schedule(edu.rit.pj2.Schedule)">schedule</a>, <a href="../../../edu/rit/pj2/Task.html#takeTuple(T)">takeTuple</a>, <a href="../../../edu/rit/pj2/Task.html#taskRank()">taskRank</a>, <a href="../../../edu/rit/pj2/Task.html#threads()">threads</a>, <a href="../../../edu/rit/pj2/Task.html#threads(int)">threads</a>, <a href="../../../edu/rit/pj2/Task.html#tryToReadTuple(T)">tryToReadTuple</a>, <a href="../../../edu/rit/pj2/Task.html#tryToTakeTuple(T)">tryToTakeTuple</a>, <a href="../../../edu/rit/pj2/Task.html#workerFor()">workerFor</a></code></li>
</ul>
<ul class="blockList">
<li class="blockList"><a name="methods_inherited_from_class_java.lang.Object">
<!-- -->
</a>
<h3>Methods inherited from class&nbsp;java.lang.<a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</a></h3>
<code><a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#clone()" title="class or interface in java.lang">clone</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#equals(java.lang.Object)" title="class or interface in java.lang">equals</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#finalize()" title="class or interface in java.lang">finalize</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#getClass()" title="class or interface in java.lang">getClass</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#hashCode()" title="class or interface in java.lang">hashCode</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#notify()" title="class or interface in java.lang">notify</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#notifyAll()" title="class or interface in java.lang">notifyAll</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#toString()" title="class or interface in java.lang">toString</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#wait()" title="class or interface in java.lang">wait</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#wait(long)" title="class or interface in java.lang">wait</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#wait(long, int)" title="class or interface in java.lang">wait</a></code></li>
</ul>
</li>
</ul>
</li>
</ul>
</div>
<div class="details">
<ul class="blockList">
<li class="blockList">
<!-- ========= CONSTRUCTOR DETAIL ======== -->
<ul class="blockList">
<li class="blockList"><a name="constructor_detail">
<!-- -->
</a>
<h3>Constructor Detail</h3>
<a name="ReducerTask()">
<!-- -->
</a>
<ul class="blockListLast">
<li class="blockList">
<h4>ReducerTask</h4>
<pre>public&nbsp;ReducerTask()</pre>
</li>
</ul>
</li>
</ul>
<!-- ============ METHOD DETAIL ========== -->
<ul class="blockList">
<li class="blockList"><a name="method_detail">
<!-- -->
</a>
<h3>Method Detail</h3>
<a name="main(java.lang.String[])">
<!-- -->
</a>
<ul class="blockListLast">
<li class="blockList">
<h4>main</h4>
<pre>public&nbsp;void&nbsp;main(<a href="http://docs.oracle.com/javase/7/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</a>[]&nbsp;args)
throws <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Exception.html?is-external=true" title="class or interface in java.lang">Exception</a></pre>
<div class="block">Reducer task main program.</div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../edu/rit/pj2/Task.html#main(java.lang.String[])">main</a></code>&nbsp;in class&nbsp;<code><a href="../../../edu/rit/pj2/Task.html" title="class in edu.rit.pj2">Task</a></code></dd>
<dt><span class="strong">Parameters:</span></dt><dd><code>args</code> - Array of command line argument strings.
<UL>
<LI><TT>args[0]</TT> = Number of mapper tasks
</UL></dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Exception.html?is-external=true" title="class or interface in java.lang">Exception</a></code> - The <TT>main()</TT> method can throw any exception.</dd></dl>
</li>
</ul>
</li>
</ul>
</li>
</ul>
</div>
</div>
<!-- ========= END OF CLASS DATA ========= -->
<!-- ======= START OF BOTTOM NAVBAR ====== -->
<div class="bottomNav"><a name="navbar_bottom">
<!-- -->
</a><a href="#skip-navbar_bottom" title="Skip navigation links"></a><a name="navbar_bottom_firstrow">
<!-- -->
</a>
<ul class="navList" title="Navigation">
<li><a href="../../../overview-summary.html">Overview</a></li>
<li><a href="package-summary.html">Package</a></li>
<li class="navBarCell1Rev">Class</li>
<li><a href="class-use/ReducerTask.html">Use</a></li>
<li><a href="package-tree.html">Tree</a></li>
<li><a href="../../../deprecated-list.html">Deprecated</a></li>
<li><a href="../../../index-files/index-1.html">Index</a></li>
<li><a href="../../../help-doc.html">Help</a></li>
</ul>
</div>
<div class="subNav">
<ul class="navList">
<li><a href="../../../edu/rit/pjmr/ReducerConfig.html" title="class in edu.rit.pjmr"><span class="strong">Prev Class</span></a></li>
<li><a href="../../../edu/rit/pjmr/ReducerTaskConfig.html" title="class in edu.rit.pjmr"><span class="strong">Next Class</span></a></li>
</ul>
<ul class="navList">
<li><a href="../../../index.html?edu/rit/pjmr/ReducerTask.html" target="_top">Frames</a></li>
<li><a href="ReducerTask.html" target="_top">No Frames</a></li>
</ul>
<ul class="navList" id="allclasses_navbar_bottom">
<li><a href="../../../allclasses-noframe.html">All Classes</a></li>
</ul>
<div>
<script type="text/javascript"><!--
allClassesLink = document.getElementById("allclasses_navbar_bottom");
if(window==top) {
allClassesLink.style.display = "block";
}
else {
allClassesLink.style.display = "none";
}
//-->
</script>
</div>
<div>
<ul class="subNavList">
<li>Summary:&nbsp;</li>
<li>Nested&nbsp;|&nbsp;</li>
<li><a href="#fields_inherited_from_class_edu.rit.pj2.Task">Field</a>&nbsp;|&nbsp;</li>
<li><a href="#constructor_summary">Constr</a>&nbsp;|&nbsp;</li>
<li><a href="#method_summary">Method</a></li>
</ul>
<ul class="subNavList">
<li>Detail:&nbsp;</li>
<li>Field&nbsp;|&nbsp;</li>
<li><a href="#constructor_detail">Constr</a>&nbsp;|&nbsp;</li>
<li><a href="#method_detail">Method</a></li>
</ul>
</div>
<a name="skip-navbar_bottom">
<!-- -->
</a></div>
<!-- ======== END OF BOTTOM NAVBAR ======= -->
<p class="legalCopy"><small><FONT SIZE="-2">Copyright &copy; 2013&ndash;2016 by Alan Kaminsky. All rights reserved. Send comments to ark</FONT><FONT SIZE="1" COLOR="#FFFFFF">&shy;</FONT><FONT SIZE="-2">&#64;</FONT><FONT SIZE="1" COLOR="#FFFFFF">&shy;</FONT><FONT SIZE="-2">cs.rit.edu.</FONT></small></p>
</body>
</html>
Reference in New Issue View Git Blame Copy Permalink