/*
* Copyright (c) 2011, 2015, 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
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*/
package com.sun.management;
import javax.management.openmbean.CompositeData;
import javax.management.openmbean.CompositeDataView;
import javax.management.openmbean.CompositeType;
import com.sun.management.internal.GarbageCollectionNotifInfoCompositeData;
/**
* The information about a garbage collection
*
* <p>
* A garbage collection notification is emitted by {@link 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:
* <ul>
* <li>The name of the garbage collector used to perform the collection.</li>
* <li>The action performed by the garbage collector.</li>
* <li>The cause of the garbage collection action.</li>
* <li>A {@link GcInfo} object containing some statistics about the GC cycle
(start time, end time) and the memory usage before and after
the GC cycle.</li>
* </ul>
*
* <p>
* A {@link CompositeData CompositeData} representing
* the {@code GarbageCollectionNotificationInfo} object
* is stored in the
* {@linkplain javax.management.Notification#setUserData userdata}
* of a {@linkplain javax.management.Notification notification}.
* The {@link #from from} method is provided to convert from
* a {@code CompositeData} to a {@code GarbageCollectionNotificationInfo}
* object. For example:
*
* <blockquote><pre>
* 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);
* ....
* }
* </pre></blockquote>
*
* <p>
* The type of the notification emitted by a {@code GarbageCollectorMXBean} is:
* <ul>
* <li>A {@linkplain #GARBAGE_COLLECTION_NOTIFICATION garbage collection notification}.
* <br>Used by every notification emitted by the garbage collector, the details about
* the notification are provided in the {@linkplain #getGcAction action} String
* </li>
* </ul>
**/
public class GarbageCollectionNotificationInfo implements CompositeDataView {
private final String gcName;
private final String gcAction;
private final String gcCause;
private final GcInfo gcInfo;
private final CompositeData cdata;
/**
* Notification type denoting that
* the Java virtual machine has completed a garbage collection cycle.
* This notification is emitted by a {@link GarbageCollectorMXBean}.
* The value of this notification type is
* {@code com.sun.management.gc.notification}.
*/
public static final String GARBAGE_COLLECTION_NOTIFICATION =
"com.sun.management.gc.notification";
/**
* Constructs a {@code GarbageCollectionNotificationInfo} object.
*
* @param gcName The name of the garbage collector used to perform the collection
* @param gcAction The name of the action performed by the garbage collector
* @param gcCause The cause of the garbage collection action
* @param gcInfo a GcInfo object providing statistics about the GC cycle
*/
public GarbageCollectionNotificationInfo(String gcName,
String gcAction,
String gcCause,
GcInfo gcInfo) {
if (gcName == null) {
throw new NullPointerException("Null gcName");
}
if (gcAction == null) {
throw new NullPointerException("Null gcAction");
}
if (gcCause == null) {
throw new NullPointerException("Null gcCause");
}
this.gcName = gcName;
this.gcAction = gcAction;
this.gcCause = gcCause;
this.gcInfo = gcInfo;
this.cdata = new GarbageCollectionNotifInfoCompositeData(this);
}
GarbageCollectionNotificationInfo(CompositeData cd) {
GarbageCollectionNotifInfoCompositeData.validateCompositeData(cd);
this.gcName = GarbageCollectionNotifInfoCompositeData.getGcName(cd);
this.gcAction = GarbageCollectionNotifInfoCompositeData.getGcAction(cd);
this.gcCause = GarbageCollectionNotifInfoCompositeData.getGcCause(cd);
this.gcInfo = GarbageCollectionNotifInfoCompositeData.getGcInfo(cd);
this.cdata = cd;
}
/**
* Returns the name of the garbage collector used to perform the collection
*
* @return the name of the garbage collector used to perform the collection
*/
public String getGcName() {
return gcName;
}
/**
* Returns the action performed by the garbage collector
*
* @return the action performed by the garbage collector
*/
public String getGcAction() {
return gcAction;
}
/**
* Returns the cause of the garbage collection
*
* @return the cause of the garbage collection
*/
public String getGcCause() {
return gcCause;
}
/**
* Returns the GC information related to the last garbage collection
*
* @return the GC information related to the
* last garbage collection
*/
public GcInfo getGcInfo() {
return gcInfo;
}
/**
* Returns a {@code GarbageCollectionNotificationInfo} object represented by the
* given {@code CompositeData}.
* The given {@code CompositeData} must contain
* the following attributes:
* <blockquote>
* <table border>
* <tr>
* <th align=left>Attribute Name</th>
* <th align=left>Type</th>
* </tr>
* <tr>
* <td>gcName</td>
* <td>{@code java.lang.String}</td>
* </tr>
* <tr>
* <td>gcAction</td>
* <td>{@code java.lang.String}</td>
* </tr>
* <tr>
* <td>gcCause</td>
* <td>{@code java.lang.String}</td>
* </tr>
* <tr>
* <td>gcInfo</td>
* <td>{@code javax.management.openmbean.CompositeData}</td>
* </tr>
* </table>
* </blockquote>
*
* @param cd {@code CompositeData} representing a
* {@code GarbageCollectionNotificationInfo}
*
* @throws IllegalArgumentException if {@code cd} does not
* represent a {@code GarbaageCollectionNotificationInfo} object.
*
* @return a {@code GarbageCollectionNotificationInfo} object represented
* by {@code cd} if {@code cd} is not {@code null};
* {@code null} otherwise.
*/
public static GarbageCollectionNotificationInfo from(CompositeData cd) {
if (cd == null) {
return null;
}
if (cd instanceof GarbageCollectionNotifInfoCompositeData) {
return ((GarbageCollectionNotifInfoCompositeData) cd).getGarbageCollectionNotifInfo();
} else {
return new GarbageCollectionNotificationInfo(cd);
}
}
public CompositeData toCompositeData(CompositeType ct) {
return cdata;
}
}