/*
* 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 sun.management.MonitorInfoCompositeData;
/**
* Information about an object monitor lock. An object monitor is locked
* when entering a synchronization block or method on that object.
*
* <h3>MXBean Mapping</h3>
* <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> ≥ 0 but <tt>stackFrame</tt> is <tt>null</tt>,
* or <tt>stackDepth</tt> < 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 summary="The attributes and their types the given CompositeData contains">
* <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);
}
}
}