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

The 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 to 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 set to 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

Since:

1.7

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)	Constructs a GarbageCollectionNotificationInfo object.

Method Summary

Modifier and Type	Method	Description
static GarbageCollectionNotificationInfo	from(CompositeData cd)	Returns a GarbageCollectionNotificationInfo object represented by the given CompositeData.
String	getGcAction()	Returns the action performed by the garbage collector
String	getGcCause()	Returns the cause of the garbage collection
GcInfo	getGcInfo()	Returns the GC information related to the last garbage collection
String	getGcName()	Returns the name of the garbage collector used to perform the collection
CompositeData	toCompositeData(CompositeType ct)	Return a CompositeData corresponding to the values in this object.

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.sun.management.gc.notification.

See Also:

• Constant Field Values

Constructor Details

GarbageCollectionNotificationInfo

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

Constructs a GarbageCollectionNotificationInfo object.

Parameters:

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

gcAction - The name of the action performed by the garbage collector

gcCause - The cause of the garbage collection action

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

Returns:

the name of the garbage collector used to perform the collection

getGcAction

public String getGcAction()

Returns the action performed by the garbage collector

Returns:

the action performed by the garbage collector

getGcCause

public String getGcCause()

Returns the cause of the garbage collection

Returns:

the cause of the garbage collection

getGcInfo

public GcInfo getGcInfo()

Returns the GC information related to the last garbage collection

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:

description

Attribute Name	Type
gcName	java.lang.String
gcAction	java.lang.String
gcCause	java.lang.String
gcInfo	javax.management.openmbean.CompositeData

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 GarbaageCollectionNotificationInfo object.

toCompositeData

public CompositeData toCompositeData(CompositeType ct)

Description copied from interface: CompositeDataView

Return a CompositeData corresponding to the values in this object. The returned value should usually be an instance of CompositeDataSupport, or a class that serializes as a CompositeDataSupport via a writeReplace method. Otherwise, a remote client that receives the object might not be able to reconstruct it.

Specified by:

toCompositeData in interface CompositeDataView

Parameters:

ct - The expected CompositeType of the returned value. If the returned value is cd, then cd.getCompositeType().equals(ct) should be true. Typically this will be because cd is a CompositeDataSupport constructed with ct as its CompositeType.

Returns:

the CompositeData.