/*

 * Copyright (c) 2011, 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.

 *

 * 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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 */

/*

 * @test

 * @bug     7036199

 * @summary Check that GarbageCollectionNotification contents are reasonable

 * @author  Frederic Parain

 * @run     main/othervm GarbageCollectionNotificationContentTest

 */

import java.util.*;

import java.lang.management.*;

import java.lang.reflect.*;

import javax.management.*;

import javax.management.openmbean.*;

import com.sun.management.GarbageCollectionNotificationInfo;

import com.sun.management.GcInfo;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.lang.reflect.Field;

public class GarbageCollectionNotificationContentTest {

    private static HashMap<String,GarbageCollectionNotificationInfo> listenerInvoked

        = new HashMap<String,GarbageCollectionNotificationInfo>();

    static volatile long count = 0;

    static volatile long number = 0;

    static Object synchronizer = new Object();

    static class GcListener implements NotificationListener {

        public void handleNotification(Notification notif, Object handback) {

            String type = notif.getType();

            if (type.equals(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION)) {

                GarbageCollectionNotificationInfo gcNotif =

                    GarbageCollectionNotificationInfo.from((CompositeData) notif.getUserData());

                String source = ((ObjectName)notif.getSource()).getCanonicalName();

                synchronized(synchronizer) {

                    if(listenerInvoked.get(source) == null) {

                            listenerInvoked.put(((ObjectName)notif.getSource()).getCanonicalName(),gcNotif);

                            count++;

                            if(count >= number) {

                                synchronizer.notify();

                            }

                    }

                }

            }

        }

    }

    public static void main(String[] args) throws Exception {

        MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();

        final Boolean isNotificationSupported = AccessController.doPrivileged (new PrivilegedAction<Boolean>() {

                public Boolean run() {

                    try {

                        Class cl = Class.forName("sun.management.VMManagementImpl");

                        Field f = cl.getDeclaredField("gcNotificationSupport");

                        f.setAccessible(true);

                        return f.getBoolean(null);

                    } catch(ClassNotFoundException e) {

                        return false;

                    } catch(NoSuchFieldException e) {

                        return false;

                    } catch(IllegalAccessException e) {

                        return false;

                    }

                }

            });

        if(!isNotificationSupported) {

            System.out.println("GC Notification not supported by the JVM, test skipped");

            return;

        }

        final ObjectName gcMXBeanPattern =

                new ObjectName("java.lang:type=GarbageCollector,*");

        Set<ObjectName> names =

                mbs.queryNames(gcMXBeanPattern, null);

        if (names.isEmpty())

            throw new Exception("Test incorrect: no GC MXBeans");

        number = names.size();

        for (ObjectName n : names) {

            if(mbs.isInstanceOf(n,"javax.management.NotificationEmitter")) {

                listenerInvoked.put(n.getCanonicalName(),null);

                GcListener listener = new GcListener();

                mbs.addNotificationListener(n, listener, null, null);

            }

        }

        // Invocation of System.gc() to trigger major GC

        System.gc();

        // Allocation of many short living and small objects to trigger minor GC

        Object data[] = new Object[32];

        for(int i = 0; i<100000000; i++) {

            data[i%32] = new int[8];

        }

        int wakeup = 0;

        synchronized(synchronizer) {

            while(count != number) {

                synchronizer.wait(10000);

                wakeup++;

                if(wakeup > 10)

                    break;

            }

        }

        for (GarbageCollectionNotificationInfo notif : listenerInvoked.values() ) {

            checkGarbageCollectionNotificationInfoContent(notif);

        }

        System.out.println("Test passed");

    }

    private static void checkGarbageCollectionNotificationInfoContent(GarbageCollectionNotificationInfo notif) throws Exception {

        System.out.println("GC notification for "+notif.getGcName());

        System.out.print("Action: "+notif.getGcAction());

        System.out.println(" Cause: "+notif.getGcCause());

        GcInfo info = notif.getGcInfo();

        System.out.print("GC Info #" + info.getId());

        System.out.print(" start:" + info.getStartTime());

        System.out.print(" end:" + info.getEndTime());

        System.out.println(" (" + info.getDuration() + "ms)");

        Map<String, MemoryUsage> usage = info.getMemoryUsageBeforeGc();

        List<String> pnames = new ArrayList<String>();

        for (Map.Entry entry : usage.entrySet() ) {

            String poolname = (String) entry.getKey();

            pnames.add(poolname);

            MemoryUsage busage = (MemoryUsage) entry.getValue();

            MemoryUsage ausage = (MemoryUsage) info.getMemoryUsageAfterGc().get(poolname);

            if (ausage == null) {

                throw new RuntimeException("After Gc Memory does not exist" +

                    " for " + poolname);

            }

            System.out.println("Usage for pool " + poolname);

            System.out.println("   Before GC: " + busage);

            System.out.println("   After GC: " + ausage);

        }

        // check if memory usage for all memory pools are returned

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

        for (MemoryPoolMXBean p : pools ) {

            if (!pnames.contains(p.getName())) {

                throw new RuntimeException("GcInfo does not contain " +

                    "memory usage for pool " + p.getName());

            }

        }

    }

}