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Code - Class EDU.oswego.cs.dl.util.concurrent.Barrier

1
2 /*
3   File: Barrier.java
4
5   Originally written by Doug Lea and released into the public domain.
6   This may be used for any purposes whatsoever without acknowledgment.
7   Thanks for the assistance and support of Sun Microsystems Labs,
8   and everyone contributing, testing, and using this code.
9
10   History:
11   Date Who What
12   11Jun1998 dl Create public version
13 */
14
15 package EDU.oswego.cs.dl.util.concurrent;
16
17 /**
18 * Barriers serve
19 * as synchronization points for groups of threads that
20 * must occasionally wait for each other.
21 * Barriers may support any of several methods that
22 * accomplish this synchronization. This interface
23 * merely expresses their minimal commonalities:
24 * <ul>
25 * <li> Every barrier is defined for a given number
26 * of <code>parties</code> -- the number of threads
27 * that must meet at the barrier point. (In all current
28 * implementations, this
29 * value is fixed upon construction of the Barrier.)
30 * <li> A barrier can become <code>broken</code> if
31 * one or more threads leave a barrier point prematurely,
32 * generally due to interruption or timeout. Corresponding
33 * synchronization methods in barriers fail, throwing
34 * BrokenBarrierException for other threads
35 * when barriers are in broken states.
36 * </ul>
37 * <p>[<a HREF="http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html"> Introduction to this package. </a>]
38
39 **/
40 public interface Barrier {
41
42
43   /**
44    * Return the number of parties that must meet per barrier
45    * point. The number of parties is always at least 1.
46    **/
47
48   public int parties();
49
50   /**
51    * Returns true if the barrier has been compromised
52    * by threads leaving the barrier before a synchronization
53    * point (normally due to interruption or timeout).
54    * Barrier methods in implementation classes throw
55    * throw BrokenBarrierException upon detection of breakage.
56    * Implementations may also support some means
57    * to clear this status.
58    **/
59
60   public boolean broken();
61 }
62