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Java > Open Source Codes > org > apache > avalon > excalibur > concurrent > ThreadBarrier


1 /*
2
3  ============================================================================
4                    The Apache Software License, Version 1.1
5  ============================================================================
6  
7  Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
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9  Redistribution and use in source and binary forms, with or without modifica-
10  tion, are permitted provided that the following conditions are met:
11  
12  1. Redistributions of source code must retain the above copyright notice,
13     this list of conditions and the following disclaimer.
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15  2. Redistributions in binary form must reproduce the above copyright notice,
16     this list of conditions and the following disclaimer in the documentation
17     and/or other materials provided with the distribution.
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19  3. The end-user documentation included with the redistribution, if any, must
20     include the following acknowledgment: "This product includes software
21     developed by the Apache Software Foundation (http://www.apache.org/)."
22     Alternately, this acknowledgment may appear in the software itself, if
23     and wherever such third-party acknowledgments normally appear.
24  
25  4. The names "Jakarta", "Avalon", "Excalibur" and "Apache Software Foundation"
26     must not be used to endorse or promote products derived from this software
27     without prior written permission. For written permission, please contact
28     apache@apache.org.
29  
30  5. Products derived from this software may not be called "Apache", nor may
31     "Apache" appear in their name, without prior written permission of the
32     Apache Software Foundation.
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34  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
35  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
36  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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39  DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
40  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
41  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
42  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
43  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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45  This software consists of voluntary contributions made by many individuals
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48  
49 */
50 package org.apache.avalon.excalibur.concurrent;
51
52 /**
53  * A thread barrier blocks all threads hitting it until a pre-defined number
54  * of threads arrive at the barrier. This is useful for implementing release
55  * consistent concurrency where you don't want to take the performance penalty
56  * of providing mutual exclusion to shared resources
57  *
58  * @deprecated use EDU.oswego.cs.dl.util.concurrent.CyclicBarrier instead
59  *
60  * @author <a HREF="mailto:kranga@sapient.com">Karthik Rangaraju</a>
61  * @version CVS $Revision: 1.5 $ $Date: 2003/04/05 19:39:33 $
62  * @since 4.0
63  */
64 public class ThreadBarrier
65 {
66     private int m_threshold;
67     private int m_count;
68
69     /**
70      * Initializes a thread barrier object with a given thread count.
71      *
72      * @param count is the number of threads that need to block on
73      * barrierSynchronize() before they will be allowed to pass through
74      * @see #barrierSynchronize()
75      */
76     public ThreadBarrier( int count )
77     {
78         m_threshold = count;
79         m_count = 0;
80     }
81
82     /**
83      * This method blocks all threads calling it until the threshold number of
84      * threads have called it. It then releases all threads blocked by it.
85      *
86      * @throws InterruptedException if any thread blocked during the call is
87      * interrupted
88      */
89     public void barrierSynchronize()
90         throws InterruptedException JavaDoc
91     {
92         synchronized( this )
93         {
94             if( m_count != m_threshold - 1 )
95             {
96                 m_count++;
97                 wait();
98             }
99             else
100             {
101                 m_count = 0;
102                 notifyAll();
103             }
104         }
105     }
106 }
107
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