Java example source code file (LockInfo.java)

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Java - Java tags/keywords

lockinfo, lockinfocompositedata, nullpointerexception, parameter, string

The LockInfo.java Java example source code

/*
 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.lang.management;

import javax.management.openmbean.CompositeData;
import java.util.concurrent.locks.*;
import sun.management.LockInfoCompositeData;

/**
 * Information about a <em>lock.  A lock can be a built-in object monitor,
 * an <em>ownable synchronizer, or the {@link Condition Condition}
 * object associated with synchronizers.
 * <p>
 * <a name="OwnableSynchronizer">An ownable synchronizer is
 * a synchronizer that may be exclusively owned by a thread and uses
 * {@link AbstractOwnableSynchronizer AbstractOwnableSynchronizer}
 * (or its subclass) to implement its synchronization property.
 * {@link ReentrantLock ReentrantLock} and
 * {@link ReentrantReadWriteLock ReentrantReadWriteLock} are
 * two examples of ownable synchronizers provided by the platform.
 *
 * <h3>MXBean Mapping
 * <tt>LockInfo is mapped to a {@link CompositeData CompositeData}
 * as specified in the {@link #from from} method.
 *
 * @see java.util.concurrent.locks.AbstractOwnableSynchronizer
 * @see java.util.concurrent.locks.Condition
 *
 * @author  Mandy Chung
 * @since   1.6
 */

public class LockInfo {

    private String className;
    private int    identityHashCode;

    /**
     * Constructs a <tt>LockInfo object.
     *
     * @param className the fully qualified name of the class of the lock object.
     * @param identityHashCode the {@link System#identityHashCode
     *                         identity hash code} of the lock object.
     */
    public LockInfo(String className, int identityHashCode) {
        if (className == null) {
            throw new NullPointerException("Parameter className cannot be null");
        }
        this.className = className;
        this.identityHashCode = identityHashCode;
    }

    /**
     * package-private constructors
     */
    LockInfo(Object lock) {
        this.className = lock.getClass().getName();
        this.identityHashCode = System.identityHashCode(lock);
    }

    /**
     * Returns the fully qualified name of the class of the lock object.
     *
     * @return the fully qualified name of the class of the lock object.
     */
    public String getClassName() {
        return className;
    }

    /**
     * Returns the identity hash code of the lock object
     * returned from the {@link System#identityHashCode} method.
     *
     * @return the identity hash code of the lock object.
     */
    public int getIdentityHashCode() {
        return identityHashCode;
    }

    /**
     * Returns a {@code LockInfo} object represented by the
     * given {@code CompositeData}.
     * The given {@code CompositeData} must contain the following attributes:
     * <blockquote>
     * <table border summary="The attributes and the types the given CompositeData contains">
     * <tr>
     *   <th align=left>Attribute Name
     *   <th align=left>Type
     * </tr>
     * <tr>
     *   <td>className