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* Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
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*/
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);
}
}
}