Class GarbageCollectionNotificationInfo

java.lang.Object

com.sun.management.GarbageCollectionNotificationInfo

All Implemented Interfaces:

CompositeDataView

public class GarbageCollectionNotificationInfo
extends Object
implements CompositeDataView

Information about a garbage collection.

A garbage collection notification is emitted by GarbageCollectorMXBean when the Java virtual machine completes a garbage collection action. The notification emitted will contain the garbage collection notification information about the status of the memory:

• The name of the garbage collector used perform the collection.
• The action performed by the garbage collector.
• The cause of the garbage collection action.
• A GcInfo object containing some statistics about the GC cycle (start time, end time) and the memory usage before and after the GC cycle.

A CompositeData representing the GarbageCollectionNotificationInfo object is stored in the userdata of a notification. The from method is provided to convert from a CompositeData to a GarbageCollectionNotificationInfo object. For example:

     Notification notif;

     // receive the notification emitted by a GarbageCollectorMXBean and save in notif
     ...

     String notifType = notif.getType();
     if (notifType.equals(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION)) {
         // retrieve the garbage collection notification information
         CompositeData cd = (CompositeData) notif.getUserData();
         GarbageCollectionNotificationInfo info = GarbageCollectionNotificationInfo.from(cd);
         ...
     }

The type of the notification emitted by a GarbageCollectorMXBean is:

• A garbage collection notification.
  Used by every notification emitted by the garbage collector, the details about the notification are provided in the action String.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	GARBAGE_COLLECTION_NOTIFICATION	Notification type denoting that the Java virtual machine has completed a garbage collection cycle.

Constructor Summary

Constructors

Constructor	Description
GarbageCollectionNotificationInfo(String gcName, String gcAction, String gcCause, GcInfo gcInfo)	Creates a new GarbageCollectionNotificationInfo instance.

Method Summary

Modifier and Type	Method	Description
static GarbageCollectionNotificationInfo	from(CompositeData cd)	Returns a GarbageCollectionNotificationInfo object represented by the given CompositeData.
String	getGcAction()
String	getGcCause()
GcInfo	getGcInfo()
String	getGcName()
CompositeData	toCompositeData(CompositeType ct)	Return the CompositeData representation of this GarbageCollectionNotificationInfo.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Field Details

GARBAGE_COLLECTION_NOTIFICATION

public static final String GARBAGE_COLLECTION_NOTIFICATION

Notification type denoting that the Java virtual machine has completed a garbage collection cycle. This notification is emitted by a GarbageCollectorMXBean. The value of this notification type is "com.ibm.lang.management.gc.notification" which matches RI naming for compatibility.

See Also:

• Constant Field Values

Constructor Details

GarbageCollectionNotificationInfo

public GarbageCollectionNotificationInfo(String gcName,
 String gcAction,
 String gcCause,
 GcInfo gcInfo)

Creates a new GarbageCollectionNotificationInfo instance.

Parameters:

gcName - the name of the garbage collector used to perform the collection

gcAction - the action of the performed by the garbage collector

gcCause - the cause the garbage collection

gcInfo - a GcInfo object providing statistics about the GC cycle

Method Details

getGcName

public String getGcName()

Returns:

the name of the garbage collector used to perform the collection.

getGcAction

public String getGcAction()

Returns:

the action of the performed by the garbage collector

getGcCause

public String getGcCause()

Returns:

the cause of the garbage collection

getGcInfo

public GcInfo getGcInfo()

Returns:

the GC information related to the last garbage collection

from

public static GarbageCollectionNotificationInfo from(CompositeData cd)

Returns a GarbageCollectionNotificationInfo object represented by the given CompositeData. The given CompositeData must contain the following attributes:

CompositeData attributes

Attribute Name	Type
gcName	java.lang.String
gcAction	java.lang.String
gcCause	java.lang.String
gcInfo	com.ibm.lang.management.GcInfo

Parameters:

cd - CompositeData representing a GarbageCollectionNotificationInfo

Returns:

a GarbageCollectionNotificationInfo object represented by cd if cd is not null; null otherwise

Throws:

IllegalArgumentException - if cd does not represent a GarbageCollectionNotificationInfo object

toCompositeData

public CompositeData toCompositeData(CompositeType ct)

Return the CompositeData representation of this GarbageCollectionNotificationInfo.

Specified by:

toCompositeData in interface CompositeDataView

Parameters:

ct - the CompositeType that the caller expects. This parameter is ignored and can be null.

Returns:

the CompositeData representation.