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 * Copyright (c) 2005, 2019, 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

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package java.lang.management;

import javax.management.openmbean.CompositeData;

import java.util.concurrent.locks.*;

import sun.management.LockInfoCompositeData;

/**

 * Information about a <em>lock</em>.  A lock can be a built-in object monitor,

 * an <em>ownable synchronizer</em>, or the {@link Condition Condition}

 * object associated with synchronizers.

 * <p>

 * <a id="OwnableSynchronizer">An ownable synchronizer</a> 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 the write-lock (but not

 * the read-lock) of {@link ReentrantReadWriteLock ReentrantReadWriteLock} are

 * two examples of ownable synchronizers provided by the platform.

 *

 * <h2><a id="MappedType">MXBean Mapping</a></h2>

 * {@code 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 {@code 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:

     * <table class="striped" style="margin-left:2em;">

     * <caption style="display:none">The attributes and the types the given CompositeData contains</caption>

     * <thead style="text-align:left">

     * <tr>

     *   <th scope="col">Attribute Name</th>

     *   <th scope="col">Type</th>

     * </tr>

     * </thead>

     * <tbody style="text-align:left">

     * <tr>

     *   <th scope="row">className</th>

     *   <td>{@code java.lang.String}</td>

     * </tr>

     * <tr>

     *   <th scope="row">identityHashCode</th>

     *   <td>{@code java.lang.Integer}</td>

     * </tr>

     * </tbody>

     * </table>

     *

     * @param cd {@code CompositeData} representing a {@code LockInfo}

     *

     * @throws IllegalArgumentException if {@code cd} does not

     *   represent a {@code LockInfo} with the attributes described

     *   above.

     * @return a {@code LockInfo} object represented

     *         by {@code cd} if {@code cd} is not {@code null};

     *         {@code null} otherwise.

     *

     * @since 1.8

     */

    public static LockInfo from(CompositeData cd) {

        if (cd == null) {

            return null;

        }

        if (cd instanceof LockInfoCompositeData) {

            return ((LockInfoCompositeData) cd).getLockInfo();

        } else {

            return LockInfoCompositeData.toLockInfo(cd);

        }

    }

    /**

     * Returns a string representation of a lock.  The returned

     * string representation consists of the name of the class of the

     * lock object, the at-sign character `@', and the unsigned

     * hexadecimal representation of the <em>identity</em> hash code

     * of the object.  This method returns a string equals to the value of:

     * <blockquote>

     * <pre>

     * lock.getClass().getName() + '@' + Integer.toHexString(System.identityHashCode(lock))

     * </pre></blockquote>

     * where {@code lock} is the lock object.

     *

     * @return the string representation of a lock.

     */

    public String toString() {

        return className + '@' + Integer.toHexString(identityHashCode);

    }

}