01: /*
02: * Copyright 1999-2000 Sun Microsystems, Inc. All Rights Reserved.
03: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04: *
05: * This code is free software; you can redistribute it and/or modify it
06: * under the terms of the GNU General Public License version 2 only, as
07: * published by the Free Software Foundation. Sun designates this
08: * particular file as subject to the "Classpath" exception as provided
09: * by Sun in the LICENSE file that accompanied this code.
10: *
11: * This code is distributed in the hope that it will be useful, but WITHOUT
12: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14: * version 2 for more details (a copy is included in the LICENSE file that
15: * accompanied this code).
16: *
17: * You should have received a copy of the GNU General Public License version
18: * 2 along with this work; if not, write to the Free Software Foundation,
19: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20: *
21: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22: * CA 95054 USA or visit www.sun.com if you need additional information or
23: * have any questions.
24: */
25:
26: package sun.awt;
27:
28: public class Mutex {
29: private boolean locked;
30: private Thread owner;
31:
32: public synchronized void lock() {
33: if (locked && Thread.currentThread() == owner) {
34: throw new IllegalMonitorStateException();
35: }
36: do {
37: if (!locked) {
38: locked = true;
39: owner = Thread.currentThread();
40: } else {
41: try {
42: wait();
43: } catch (InterruptedException e) {
44: // try again
45: }
46: }
47: } while (owner != Thread.currentThread());
48: }
49:
50: public synchronized void unlock() {
51: if (Thread.currentThread() != owner) {
52: throw new IllegalMonitorStateException();
53: }
54: owner = null;
55: locked = false;
56: notify();
57: }
58:
59: protected boolean isOwned() {
60: return (locked && Thread.currentThread() == owner);
61: }
62: }
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