/*

 * Copyright (c) 2005, 2006, 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 sun.management.MonitorInfoCompositeData;

/**

 * Information about an object monitor lock.  An object monitor is locked

 * when entering a synchronization block or method on that object.

 *

 * <h4>MXBean Mapping</h4>

 * <tt>MonitorInfo</tt> is mapped to a {@link CompositeData CompositeData}

 * with attributes as specified in

 * the {@link #from from} method.

 *

 * @author  Mandy Chung

 * @since   1.6

 */

public class MonitorInfo extends LockInfo {

    private int    stackDepth;

    private StackTraceElement stackFrame;

    /**

     * Construct a <tt>MonitorInfo</tt> 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.

     * @param stackDepth the depth in the stack trace where the object monitor

     *                   was locked.

     * @param stackFrame the stack frame that locked the object monitor.

     * @throws IllegalArgumentException if

     *    <tt>stackDepth</tt> &ge; 0 but <tt>stackFrame</tt> is <tt>null</tt>,

     *    or <tt>stackDepth</tt> &lt; 0 but <tt>stackFrame</tt> is not

     *       <tt>null</tt>.

     */

    public MonitorInfo(String className,

                       int identityHashCode,

                       int stackDepth,

                       StackTraceElement stackFrame) {

        super(className, identityHashCode);

        if (stackDepth >= 0 && stackFrame == null) {

            throw new IllegalArgumentException("Parameter stackDepth is " +

                stackDepth + " but stackFrame is null");

        }

        if (stackDepth < 0 && stackFrame != null) {

            throw new IllegalArgumentException("Parameter stackDepth is " +

                stackDepth + " but stackFrame is not null");

        }

        this.stackDepth = stackDepth;

        this.stackFrame = stackFrame;

    }

    /**

     * Returns the depth in the stack trace where the object monitor

     * was locked.  The depth is the index to the <tt>StackTraceElement</tt>

     * array returned in the {@link ThreadInfo#getStackTrace} method.

     *

     * @return the depth in the stack trace where the object monitor

     *         was locked, or a negative number if not available.

     */

    public int getLockedStackDepth() {

        return stackDepth;

    }

    /**

     * Returns the stack frame that locked the object monitor.

     *

     * @return <tt>StackTraceElement</tt> that locked the object monitor,

     *         or <tt>null</tt> if not available.

     */

    public StackTraceElement getLockedStackFrame() {

        return stackFrame;

    }

    /**

     * Returns a <tt>MonitorInfo</tt> object represented by the

     * given <tt>CompositeData</tt>.

     * The given <tt>CompositeData</tt> must contain the following attributes

     * as well as the attributes specified in the

     * <a href="LockInfo.html#MappedType">

     * mapped type</a> for the {@link LockInfo} class:

     * <blockquote>

     * <table border>

     * <tr>

     *   <th align=left>Attribute Name</th>

     *   <th align=left>Type</th>

     * </tr>

     * <tr>

     *   <td>lockedStackFrame</td>

     *   <td><tt>CompositeData as specified in the

     *       <a href="ThreadInfo.html#StackTrace">stackTrace</a>

     *       attribute defined in the {@link ThreadInfo#from

     *       ThreadInfo.from} method.

     *       </tt></td>

     * </tr>

     * <tr>

     *   <td>lockedStackDepth</td>

     *   <td><tt>java.lang.Integer</tt></td>

     * </tr>

     * </table>

     * </blockquote>

     *

     * @param cd <tt>CompositeData</tt> representing a <tt>MonitorInfo</tt>

     *

     * @throws IllegalArgumentException if <tt>cd</tt> does not

     *   represent a <tt>MonitorInfo</tt> with the attributes described

     *   above.

     * @return a <tt>MonitorInfo</tt> object represented

     *         by <tt>cd</tt> if <tt>cd</tt> is not <tt>null</tt>;

     *         <tt>null</tt> otherwise.

     */

    public static MonitorInfo from(CompositeData cd) {

        if (cd == null) {

            return null;

        }

        if (cd instanceof MonitorInfoCompositeData) {

            return ((MonitorInfoCompositeData) cd).getMonitorInfo();

        } else {

            MonitorInfoCompositeData.validateCompositeData(cd);

            String className = MonitorInfoCompositeData.getClassName(cd);

            int identityHashCode = MonitorInfoCompositeData.getIdentityHashCode(cd);

            int stackDepth = MonitorInfoCompositeData.getLockedStackDepth(cd);

            StackTraceElement stackFrame = MonitorInfoCompositeData.getLockedStackFrame(cd);

            return new MonitorInfo(className,

                                   identityHashCode,

                                   stackDepth,

                                   stackFrame);

        }

    }

}