001: /*
002: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
003: *
004: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
005: *
006: * The contents of this file are subject to the terms of either the GNU
007: * General Public License Version 2 only ("GPL") or the Common
008: * Development and Distribution License("CDDL") (collectively, the
009: * "License"). You may not use this file except in compliance with the
010: * License. You can obtain a copy of the License at
011: * http://www.netbeans.org/cddl-gplv2.html
012: * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
013: * specific language governing permissions and limitations under the
014: * License. When distributing the software, include this License Header
015: * Notice in each file and include the License file at
016: * nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
017: * particular file as subject to the "Classpath" exception as provided
018: * by Sun in the GPL Version 2 section of the License file that
019: * accompanied this code. If applicable, add the following below the
020: * License Header, with the fields enclosed by brackets [] replaced by
021: * your own identifying information:
022: * "Portions Copyrighted [year] [name of copyright owner]"
023: *
024: * Contributor(s):
025: *
026: * The Original Software is NetBeans. The Initial Developer of the Original
027: * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
028: * Microsystems, Inc. All Rights Reserved.
029: *
030: * If you wish your version of this file to be governed by only the CDDL
031: * or only the GPL Version 2, indicate your decision by adding
032: * "[Contributor] elects to include this software in this distribution
033: * under the [CDDL or GPL Version 2] license." If you do not indicate a
034: * single choice of license, a recipient has the option to distribute
035: * your version of this file under either the CDDL, the GPL Version 2 or
036: * to extend the choice of license to its licensees as provided above.
037: * However, if you add GPL Version 2 code and therefore, elected the GPL
038: * Version 2 license, then the option applies only if the new code is
039: * made subject to such option by the copyright holder.
040: */
041:
042: package threaddemo.locking;
043:
044: // XXX need test
045:
046: // XXX could track read vs. write state
047:
048: /**
049: * Simple lock that actually just uses a simple synchronization monitor.
050: * @author Jesse Glick
051: */
052: final class MonitorLock implements RWLock {
053:
054: private final Object monitor;
055:
056: MonitorLock(Object monitor) {
057: this .monitor = monitor;
058: }
059:
060: public boolean canRead() {
061: return Thread.holdsLock(monitor);
062: }
063:
064: public <T, E extends Exception> T read(
065: LockExceptionAction<T, E> action) throws E {
066: synchronized (monitor) {
067: return action.run();
068: }
069: }
070:
071: public <T> T read(LockAction<T> action) {
072: synchronized (monitor) {
073: return action.run();
074: }
075: }
076:
077: public void read(Runnable action) {
078: synchronized (monitor) {
079: action.run();
080: }
081: }
082:
083: public void readLater(final Runnable action) {
084: Worker.start(new Runnable() {
085: public void run() {
086: read(action);
087: }
088: });
089: }
090:
091: public void write(Runnable action) {
092: read(action);
093: }
094:
095: public boolean canWrite() {
096: return canRead();
097: }
098:
099: public <T> T write(LockAction<T> action) {
100: return read(action);
101: }
102:
103: public <T, E extends Exception> T write(
104: LockExceptionAction<T, E> action) throws E {
105: return read(action);
106: }
107:
108: public void writeLater(Runnable action) {
109: readLater(action);
110: }
111:
112: public String toString() {
113: return "MonitorLock<monitor=" + monitor + ">";
114: }
115:
116: }
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