001 /*
002 * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package java.lang.management;
027
028 import javax.management.openmbean.CompositeData;
029 import java.util.concurrent.locks.*;
030 import java.beans.ConstructorProperties;
031
032 /**
033 * Information about a <em>lock</em>. A lock can be a built-in object monitor,
034 * an <em>ownable synchronizer</em>, or the {@link Condition Condition}
035 * object associated with synchronizers.
036 * <p>
037 * <a name="OwnableSynchronizer">An ownable synchronizer</a> is
038 * a synchronizer that may be exclusively owned by a thread and uses
039 * {@link AbstractOwnableSynchronizer AbstractOwnableSynchronizer}
040 * (or its subclass) to implement its synchronization property.
041 * {@link ReentrantLock ReentrantLock} and
042 * {@link ReentrantReadWriteLock ReentrantReadWriteLock} are
043 * two examples of ownable synchronizers provided by the platform.
044 *
045 * <h4><a name="MappedType">MXBean Mapping</a></h4>
046 * <tt>LockInfo</tt> is mapped to a {@link CompositeData CompositeData}
047 * as specified in the <a href="../../../javax/management/MXBean.html#mapping-rules">
048 * type mapping rules</a> of {@linkplain javax.management.MXBean MXBeans}.
049 *
050 * @see java.util.concurrent.locks.AbstractOwnableSynchronizer
051 * @see java.util.concurrent.locks.Condition
052 *
053 * @author Mandy Chung
054 * @version 1.12, 05/05/07
055 * @since 1.6
056 */
057
058 public class LockInfo {
059
060 private String className;
061 private int identityHashCode;
062
063 /**
064 * Constructs a <tt>LockInfo</tt> object.
065 *
066 * @param className the fully qualified name of the class of the lock object.
067 * @param identityHashCode the {@link System#identityHashCode
068 * identity hash code} of the lock object.
069 */
070 @ConstructorProperties({"className","identityHashCode"})
071 public LockInfo(String className, int identityHashCode) {
072 if (className == null) {
073 throw new NullPointerException(
074 "Parameter className cannot be null");
075 }
076 this .className = className;
077 this .identityHashCode = identityHashCode;
078 }
079
080 /**
081 * package-private constructors
082 */
083 LockInfo(Object lock) {
084 this .className = lock.getClass().getName();
085 this .identityHashCode = System.identityHashCode(lock);
086 }
087
088 /**
089 * Returns the fully qualified name of the class of the lock object.
090 *
091 * @return the fully qualified name of the class of the lock object.
092 */
093 public String getClassName() {
094 return className;
095 }
096
097 /**
098 * Returns the identity hash code of the lock object
099 * returned from the {@link System#identityHashCode} method.
100 *
101 * @return the identity hash code of the lock object.
102 */
103 public int getIdentityHashCode() {
104 return identityHashCode;
105 }
106
107 /**
108 * Returns a string representation of a lock. The returned
109 * string representation consists of the name of the class of the
110 * lock object, the at-sign character `@', and the unsigned
111 * hexadecimal representation of the <em>identity</em> hash code
112 * of the object. This method returns a string equals to the value of:
113 * <blockquote>
114 * <pre>
115 * lock.getClass().getName() + '@' + Integer.toHexString(System.identityHashCode(lock))
116 * </pre></blockquote>
117 * where <tt>lock</tt> is the lock object.
118 *
119 * @return the string representation of a lock.
120 */
121 public String toString() {
122 return className + '@' + Integer.toHexString(identityHashCode);
123 }
124 }
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