Module jdk.management

Package com.sun.management

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 java.lang.Object

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

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.