/*

 * Copyright (c) 2003, 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.internal;

import com.sun.management.GarbageCollectionNotificationInfo;

import com.sun.management.GarbageCollectorMXBean;

import com.sun.management.GcInfo;

import java.lang.management.ManagementFactory;

import java.lang.management.MemoryPoolMXBean;

import java.util.List;

import javax.management.ListenerNotFoundException;

import javax.management.MBeanNotificationInfo;

import javax.management.Notification;

import javax.management.NotificationFilter;

import javax.management.NotificationListener;

import javax.management.openmbean.CompositeData;

import sun.management.GarbageCollectorImpl;

/**

 * Implementation class for the garbage collector.

 * Standard and committed hotspot-specific metrics if any.

 *

 * ManagementFactory.getGarbageCollectorMXBeans() returns a list

 * of instances of this class.

 */

public class GarbageCollectorExtImpl extends GarbageCollectorImpl

    implements GarbageCollectorMXBean {

    public GarbageCollectorExtImpl(String name) {

        super(name);

    }

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

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

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

    private String[] poolNames = null;

    private synchronized String[] getAllPoolNames() {

        if (poolNames == null) {

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

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

            int i = 0;

            for (MemoryPoolMXBean m : pools) {

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

            }

        }

        return poolNames;

    }

    public GcInfo getLastGcInfo() {

        GcInfo info = getGcInfoBuilder().getLastGcInfo();

        return info;

    }

    private final static String notifName =

        "javax.management.Notification";

    private final static String[] gcNotifTypes = {

        GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION

    };

    private MBeanNotificationInfo[] notifInfo = null;

    public MBeanNotificationInfo[] getNotificationInfo() {

        synchronized (this) {

            if (notifInfo == null) {

                 notifInfo = new MBeanNotificationInfo[1];

                 notifInfo[0] = new MBeanNotificationInfo(gcNotifTypes,

                                                          notifName,

                                                          "GC Notification");

            }

        }

        return notifInfo;

    }

    private static long seqNumber = 0;

    private static long getNextSeqNumber() {

        return ++seqNumber;

    }

    protected void createGCNotification(long timestamp,

                              String gcName,

                              String gcAction,

                              String gcCause,

                              GcInfo gcInfo)  {

        if (!hasListeners()) {

            return;

        }

        Notification notif = new Notification(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION,

                                              getObjectName(),

                                              getNextSeqNumber(),

                                              timestamp,

                                              gcName);

        GarbageCollectionNotificationInfo info =

            new GarbageCollectionNotificationInfo(gcName,

                                                  gcAction,

                                                  gcCause,

                                                  gcInfo);

        CompositeData cd =

            GarbageCollectionNotifInfoCompositeData.toCompositeData(info);

        notif.setUserData(cd);

        sendNotification(notif);

    }

    public synchronized void addNotificationListener(NotificationListener listener,

                                                     NotificationFilter filter,

                                                     Object handback)

    {

        boolean before = hasListeners();

        super.addNotificationListener(listener, filter, handback);

        boolean after = hasListeners();

        if (!before && after) {

            setNotificationEnabled(this, true);

        }

    }

    public synchronized void removeNotificationListener(NotificationListener listener)

        throws ListenerNotFoundException {

        boolean before = hasListeners();

        super.removeNotificationListener(listener);

        boolean after = hasListeners();

        if (before && !after) {

            setNotificationEnabled(this,false);

        }

    }

    public synchronized void removeNotificationListener(NotificationListener listener,

                                                        NotificationFilter filter,

                                                        Object handback)

            throws ListenerNotFoundException

    {

        boolean before = hasListeners();

        super.removeNotificationListener(listener,filter,handback);

        boolean after = hasListeners();

        if (before && !after) {

            setNotificationEnabled(this,false);

        }

    }

    private GcInfoBuilder gcInfoBuilder;

    // Invoked also by the VM

    private synchronized GcInfoBuilder getGcInfoBuilder() {

        if(gcInfoBuilder == null) {

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

        }

        return gcInfoBuilder;

    }

    private native void setNotificationEnabled(GarbageCollectorMXBean gc,

                                                 boolean enabled);

    // Invoked by the VM

    private static java.lang.management.GarbageCollectorMXBean

        createGarbageCollector(String name, String type) {

        return new GarbageCollectorExtImpl(name);

    }

}