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annotate src/EDU/oswego/cs/dl/util/concurrent/NullSync.java @ 27:511648fa4d64 Version 2.1

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Version to 2.1
author Dan Creswell <dan.creswell@gmail.com>
date Mon, 04 Jan 2010 13:00:40 +0000
parents 3dc0c5604566
children
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1 /*
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2 File: NullSync.java
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4 Originally written by Doug Lea and released into the public domain.
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5 This may be used for any purposes whatsoever without acknowledgment.
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6 Thanks for the assistance and support of Sun Microsystems Labs,
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7 and everyone contributing, testing, and using this code.
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8
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9 History:
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10 Date Who What
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11 1Aug1998 dl Create public version
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12 */
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14 package EDU.oswego.cs.dl.util.concurrent;
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16 /**
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17 * A No-Op implementation of Sync. Acquire never blocks,
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18 * Attempt always succeeds, Release has no effect.
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19 * However, acquire and release do detect interruption
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20 * and throw InterruptedException. Also, the methods
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21 * are synchronized, so preserve memory barrier properties
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22 * of Syncs.
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23 * <p>
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24 * NullSyncs can be useful in optimizing classes when
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25 * it is found that locking is not strictly necesssary.
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26 *
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27 * <p>[<a href="http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html"> Introduction to this package. </a>]
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28 **/
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31 public class NullSync implements Sync {
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32
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33 public synchronized void acquire() throws InterruptedException {
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34 if (Thread.interrupted()) throw new InterruptedException();
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35 }
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37 public synchronized boolean attempt(long msecs) throws InterruptedException {
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38 if (Thread.interrupted()) throw new InterruptedException();
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39 return true;
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40 }
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42 public synchronized void release() {}
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45 }
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