1 /*

     2  * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package com.sun.management.internal;

    27 

    28 import com.sun.management.GarbageCollectionNotificationInfo;

    29 import com.sun.management.GarbageCollectorMXBean;

    30 import com.sun.management.GcInfo;

    31 import java.lang.management.ManagementFactory;

    32 import java.lang.management.MemoryPoolMXBean;

    33 import java.util.List;

    34 import javax.management.ListenerNotFoundException;

    35 import javax.management.MBeanNotificationInfo;

    36 import javax.management.Notification;

    37 import javax.management.NotificationFilter;

    38 import javax.management.NotificationListener;

    39 import javax.management.openmbean.CompositeData;

    40 import sun.management.GarbageCollectorImpl;

    41 

    42 /**

    43  * Implementation class for the garbage collector.

    44  * Standard and committed hotspot-specific metrics if any.

    45  *

    46  * ManagementFactory.getGarbageCollectorMXBeans() returns a list

    47  * of instances of this class.

    48  */

    49 public class GarbageCollectorExtImpl extends GarbageCollectorImpl

    50     implements GarbageCollectorMXBean {

    51 

    52     public GarbageCollectorExtImpl(String name) {

    53         super(name);

    54     }

    55 

    56     // The memory pools are static and won't be changed.

    57     // TODO: If the hotspot implementation begins to have pools

    58     // dynamically created and removed, this needs to be modified.

    59     private String[] poolNames = null;

    60     private synchronized String[] getAllPoolNames() {

    61         if (poolNames == null) {

    62             List<MemoryPoolMXBean> pools = ManagementFactory.getMemoryPoolMXBeans();

    63             poolNames = new String[pools.size()];

    64             int i = 0;

    65             for (MemoryPoolMXBean m : pools) {

    66                 poolNames[i++] = m.getName();

    67             }

    68         }

    69         return poolNames;

    70     }

    71 

    72     public GcInfo getLastGcInfo() {

    73         GcInfo info = getGcInfoBuilder().getLastGcInfo();

    74         return info;

    75     }

    76 

    77     private final static String notifName =

    78         "javax.management.Notification";

    79 

    80     private final static String[] gcNotifTypes = {

    81         GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION

    82     };

    83 

    84     private MBeanNotificationInfo[] notifInfo = null;

    85     public MBeanNotificationInfo[] getNotificationInfo() {

    86         synchronized (this) {

    87             if (notifInfo == null) {

    88                  notifInfo = new MBeanNotificationInfo[1];

    89                  notifInfo[0] = new MBeanNotificationInfo(gcNotifTypes,

    90                                                           notifName,

    91                                                           "GC Notification");

    92             }

    93         }

    94         return notifInfo;

    95     }

    96 

    97     private static long seqNumber = 0;

    98     private static long getNextSeqNumber() {

    99         return ++seqNumber;

   100     }

   101 

   102     protected void createGCNotification(long timestamp,

   103                               String gcName,

   104                               String gcAction,

   105                               String gcCause,

   106                               GcInfo gcInfo)  {

   107         if (!hasListeners()) {

   108             return;

   109         }

   110         Notification notif = new Notification(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION,

   111                                               getObjectName(),

   112                                               getNextSeqNumber(),

   113                                               timestamp,

   114                                               gcName);

   115         GarbageCollectionNotificationInfo info =

   116             new GarbageCollectionNotificationInfo(gcName,

   117                                                   gcAction,

   118                                                   gcCause,

   119                                                   gcInfo);

   120 

   121         CompositeData cd =

   122             GarbageCollectionNotifInfoCompositeData.toCompositeData(info);

   123         notif.setUserData(cd);

   124         sendNotification(notif);

   125     }

   126 

   127     public synchronized void addNotificationListener(NotificationListener listener,

   128                                                      NotificationFilter filter,

   129                                                      Object handback)

   130     {

   131         boolean before = hasListeners();

   132         super.addNotificationListener(listener, filter, handback);

   133         boolean after = hasListeners();

   134         if (!before && after) {

   135             setNotificationEnabled(this, true);

   136         }

   137     }

   138 

   139     public synchronized void removeNotificationListener(NotificationListener listener)

   140         throws ListenerNotFoundException {

   141         boolean before = hasListeners();

   142         super.removeNotificationListener(listener);

   143         boolean after = hasListeners();

   144 

   145         if (before && !after) {

   146             setNotificationEnabled(this,false);

   147         }

   148     }

   149 

   150     public synchronized void removeNotificationListener(NotificationListener listener,

   151                                                         NotificationFilter filter,

   152                                                         Object handback)

   153             throws ListenerNotFoundException

   154     {

   155         boolean before = hasListeners();

   156         super.removeNotificationListener(listener,filter,handback);

   157         boolean after = hasListeners();

   158         if (before && !after) {

   159             setNotificationEnabled(this,false);

   160         }

   161     }

   162 

   163     private GcInfoBuilder gcInfoBuilder;

   164     // Invoked also by the VM

   165     private synchronized GcInfoBuilder getGcInfoBuilder() {

   166         if(gcInfoBuilder == null) {

   167             gcInfoBuilder = new GcInfoBuilder(this, getAllPoolNames());

   168         }

   169         return gcInfoBuilder;

   170     }

   171 

   172     private native void setNotificationEnabled(GarbageCollectorMXBean gc,

   173                                                  boolean enabled);

   174 

   175     // Invoked by the VM

   176     private static java.lang.management.GarbageCollectorMXBean

   177         createGarbageCollector(String name, String type) {

   178 

   179         return new GarbageCollectorExtImpl(name);

   180     }

   181 }