/*

 * 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

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

 * questions.

 */

/*

 * @test TestFullGCount.java

 * @bug 7072527

 * @summary CMS: JMM GC counters overcount in some cases

 * @run main/othervm -XX:+UseConcMarkSweepGC TestFullGCCount

 *

 */

import java.util.*;

import java.lang.management.*;

public class TestFullGCCount {

    public String collectorName = "ConcurrentMarkSweep";

    public static void main(String [] args) {

        TestFullGCCount t = null;

        if (args.length==2) {

            t = new TestFullGCCount(args[0], args[1]);

        } else {

            t = new TestFullGCCount();

        }

        System.out.println("Monitoring collector: " + t.collectorName);

        t.run();

    }

    public TestFullGCCount(String pool, String collector) {

        collectorName = collector;

    }

    public TestFullGCCount() {

    }

    public void run() {

        int count = 0;

        int iterations = 20;

        long counts[] = new long[iterations];

        boolean diffAlways2 = true; // assume we will fail

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

            System.gc();

            counts[i] = getCollectionCount();

            if (i>0) {

                if (counts[i] - counts[i-1] != 2) {

                    diffAlways2 = false;

                }

            }

        }

        if (diffAlways2) {

            throw new RuntimeException("FAILED: System.gc must be incrementing count twice.");

        }

        System.out.println("Passed.");

    }

    private long getCollectionCount() {

        long count = 0;

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

        List<GarbageCollectorMXBean> collectors = ManagementFactory.getGarbageCollectorMXBeans();

        for (int i=0; i<collectors.size(); i++) {

            GarbageCollectorMXBean collector = collectors.get(i);

            String name = collector.getName();

            if (name.contains(collectorName)) {

                System.out.println(name + ": collection count = "

                                   + collector.getCollectionCount());

                count = collector.getCollectionCount();

            }

        }

        return count;

    }

}