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Java > Open Source Codes > org > jruby > internal > runtime > AtomicSpinlock


1 /***** BEGIN LICENSE BLOCK *****
2  * Version: CPL 1.0/GPL 2.0/LGPL 2.1
3  *
4  * The contents of this file are subject to the Common Public
5  * License Version 1.0 (the "License"); you may not use this file
6  * except in compliance with the License. You may obtain a copy of
7  * the License at http://www.eclipse.org/legal/cpl-v10.html
8  *
9  * Software distributed under the License is distributed on an "AS
10  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
11  * implied. See the License for the specific language governing
12  * rights and limitations under the License.
13  *
14  * Copyright (C) 2004 Charles O Nutter <headius@headius.com>
15  * Copyright (C) 2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
16  *
17  * Alternatively, the contents of this file may be used under the terms of
18  * either of the GNU General Public License Version 2 or later (the "GPL"),
19  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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27  * the terms of any one of the CPL, the GPL or the LGPL.
28  ***** END LICENSE BLOCK *****/
29 package org.jruby.internal.runtime;
30
31 /**
32  * A spinlock.
33  *
34  * @author cnutter
35  */
36 public class AtomicSpinlock {
37     private volatile int counter;
38     
39     public AtomicSpinlock() {
40         // FIXME is this correct?
41 counter = 0;
42     }
43     
44     public AtomicSpinlock(int start) {
45         counter = start;
46     }
47     
48     public synchronized void increment() {
49         counter++;
50         notify();
51     }
52     
53     public synchronized void decrement() {
54         counter--;
55         notify();
56     }
57     
58     public synchronized void waitForZero(long timeout) throws InterruptedException JavaDoc {
59         // TODO: timeout isn't really doing what I want here.
60 while (counter > 0) {
61             timeWait(timeout);
62         }
63     }
64     
65     public synchronized void waitForValue(long timeout, int value) throws InterruptedException JavaDoc {
66         while (counter != value) {
67             timeWait(timeout);
68         }
69     }
70     
71     private void timeWait(long timeout) throws InterruptedException JavaDoc {
72         if (timeout > 0) wait(timeout);
73         else wait();
74     }
75 }
76
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