142 lines
3.5 KiB
Java
142 lines
3.5 KiB
Java
//******************************************************************************
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//
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// File: PairTuple.java
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// Package: edu.rit.pjmr
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// Unit: Class edu.rit.pjmr.PairTuple
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//
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// This Java source file is copyright (C) 2015 by Alan Kaminsky. All rights
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// reserved. For further information, contact the author, Alan Kaminsky, at
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// ark@cs.rit.edu.
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//
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// This Java source file is part of the Parallel Java 2 Library ("PJ2"). PJ2 is
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// free software; you can redistribute it and/or modify it under the terms of
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// the GNU General Public License as published by the Free Software Foundation;
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// either version 3 of the License, or (at your option) any later version.
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//
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// PJ2 is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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// A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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//
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// A copy of the GNU General Public License is provided in the file gpl.txt. You
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// may also obtain a copy of the GNU General Public License on the World Wide
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// Web at http://www.gnu.org/licenses/gpl.html.
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//
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//******************************************************************************
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package edu.rit.pjmr;
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import edu.rit.io.InStream;
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import edu.rit.io.OutStream;
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import edu.rit.pj2.Tuple;
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import edu.rit.pj2.Vbl;
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import edu.rit.util.AList;
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import edu.rit.util.Pair;
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import java.io.ByteArrayInputStream;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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/**
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* Class PairTuple is a tuple that contains a list of (key, value) pairs from a
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* mapper task.
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*
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* @param <K> Key data type.
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* @param <V> Value data type; must implement interface {@linkplain
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* edu.rit.pj2.Vbl Vbl}.
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*
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* @author Alan Kaminsky
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* @version 12-Jan-2015
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*/
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class PairTuple<K,V extends Vbl>
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extends Tuple
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{
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// Hidden data members.
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private byte[] content;
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// Exported constructors.
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/**
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* Construct a new pair tuple with a null pair list.
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*/
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public PairTuple()
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{
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}
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/**
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* Construct a new pair tuple with the given pair list.
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*
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* @param pairList Pair list, or null.
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*
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* @exception IOException
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* Thrown if an I/O error occurred while streaming the pair list.
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*/
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public PairTuple
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(AList<Pair<K,V>> pairList)
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throws IOException
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{
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if (pairList != null)
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{
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ByteArrayOutputStream baos = new ByteArrayOutputStream();
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OutStream out = new OutStream (baos);
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out.writeObject (pairList);
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out.close();
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content = baos.toByteArray();
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}
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}
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// Exported operations.
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/**
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* Get this pair tuple's list of pairs.
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*
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* @return Pair list, or null.
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*
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* @exception IOException
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* Thrown if an I/O error occurred while destreaming the pair list.
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*/
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public AList<Pair<K,V>> pairList()
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throws IOException
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{
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if (content == null)
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return null;
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else
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{
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ByteArrayInputStream bais = new ByteArrayInputStream (content);
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InStream in = new InStream (bais);
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return (AList<Pair<K,V>>) in.readObject();
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}
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}
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/**
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* Write this pair tuple to the given out stream.
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*
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* @param out Out stream.
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*
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* @exception IOException
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* Thrown if an I/O error occurred.
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*/
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public void writeOut
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(OutStream out)
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throws IOException
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{
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out.writeByteArray (content);
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}
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/**
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* Read this pair tuple from the given in stream.
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*
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* @param in In stream.
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*
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* @exception IOException
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* Thrown if an I/O error occurred.
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*/
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public void readIn
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(InStream in)
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throws IOException
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{
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content = in.readByteArray();
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}
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}
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