/*

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 * 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.

 *

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 */

/*

 * @test

 * @bug     5086470

 * @key intermittent

 * @summary Basic Test for the following methods:

 *          - ThreadMXBean.findDeadlockedThreads()

 *          - ThreadMXBean.findMonitorDeadlockedThreads()

 * @author  Mandy Chung

 *

 * @build MonitorDeadlock

 * @build SynchronizerDeadlock

 * @build ThreadDump

 * @run main/othervm FindDeadlocks

 */

import java.lang.management.*;

import java.util.*;

public class FindDeadlocks {

    static ThreadMXBean mbean = ManagementFactory.getThreadMXBean();

    public static void main(String[] argv) {

        ThreadMXBean mbean = ManagementFactory.getThreadMXBean();

        // create deadlocked threads

        MonitorDeadlock md = new MonitorDeadlock();

        // no deadlock

        if (findDeadlocks() != null) {

            throw new RuntimeException("TEST FAILED: Should return null.");

        }

        // Let the threads to proceed

        md.goDeadlock();

        // wait until the deadlock is ready

        md.waitUntilDeadlock();

        long[] mthreads = findDeadlocks();

        if (mthreads == null) {

            ThreadDump.dumpStacks();

            throw new RuntimeException("TEST FAILED: Deadlock not detected.");

        }

        md.checkResult(mthreads);

        // create deadlocked threads on synchronizers

        SynchronizerDeadlock sd = new SynchronizerDeadlock();

        // Let the threads to proceed

        sd.goDeadlock();

        // wait until the deadlock is ready

        sd.waitUntilDeadlock();

        // Find Deadlock

        long[] threads = findDeadlocks();

        if (threads == null) {

            ThreadDump.dumpStacks();

            throw new RuntimeException("TEST FAILED: Deadlock not detected.");

        }

        // form a list of newly deadlocked threads

        long[] newList = new long[threads.length - mthreads.length];

        int count = 0;

        for (int i = 0; i < threads.length; i++) {

            long id = threads[i];

            boolean isNew = true;

            for (int j = 0; j < mthreads.length; j++) {

                if (mthreads[j] == id) {

                    isNew = false;

                    break;

                }

            }

            if (isNew) {

                newList[count++] = id;

            }

        }

        if (mbean.isSynchronizerUsageSupported()) {

            sd.checkResult(newList);

        } else {

            // monitoring of synchronizer usage not supported

            if (count != 0) {

                throw new RuntimeException("TEST FAILED: NewList should be empty.");

            }

        }

        // Print Deadlock stack trace

        System.out.println("Found threads that are in deadlock:-");

        ThreadInfo[] infos = mbean.getThreadInfo(threads, Integer.MAX_VALUE);

        for (int i = 0; i < infos.length; i++) {

            ThreadDump.printThreadInfo(infos[i]);

        }

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

    }

    static long[] findDeadlocks() {

        long[] threads;

        if (mbean.isSynchronizerUsageSupported()) {

            threads = mbean.findDeadlockedThreads();

        } else {

            threads = mbean.findMonitorDeadlockedThreads();

        }

        return threads;

    }

}