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/*

 * @test

 * @bug     4530538

 * @summary Basic unit test of mbean.getThreadCount()

 *                             mbean.getTotalStartedThreadCount()

 *                             mbean.getPeakThreadCount()

 *                             mbean.getDaemonThreadCount()

 * @author  Alexei Guibadoulline

 *

 * @run main ThreadCounts

 */

import java.lang.management.*;

public class ThreadCounts {

    final static int DAEMON_THREADS = 21;

    final static int USER_THREADS_1 = 11;

    final static int USER_THREADS_2 = 9;

    final static int USER_THREADS = USER_THREADS_1 + USER_THREADS_2;

    final static int ALL_THREADS = DAEMON_THREADS + USER_THREADS;

    private static volatile boolean live[] = new boolean[ALL_THREADS];

    private ThreadMXBean mbean = ManagementFactory.getThreadMXBean();

    private static boolean testFailed = false;

    // barrier for threads communication

    private static Barrier barrier = new Barrier(DAEMON_THREADS);

    public static void main(String argv[]) {

        ThreadCounts test = new ThreadCounts();

        Thread allThreads[] = new Thread[ALL_THREADS];

        // Start DAEMON_THREADS threads and wait to be sure they all are alive

        barrier.set(DAEMON_THREADS);

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

            live[i] = true;

            allThreads[i] = new MyThread(i);

            allThreads[i].setDaemon(true);

            allThreads[i].start();

        }

        // wait until all threads have started.

        barrier.await();

        System.out.println("Number of daemon threads added = " +

                           DAEMON_THREADS);

        // Check mbean now

        if ( (!test.checkCount  (DAEMON_THREADS)) ||

             (!test.checkCreated(DAEMON_THREADS)) ||

             (!test.checkPeak   (DAEMON_THREADS)) ||

             (!test.checkDaemon (DAEMON_THREADS))

           )

            testFailed = true;

        // Start USER_THREADS_1 threads and wait to be sure they all are alive

        barrier.set(USER_THREADS_1);

        for (int i = DAEMON_THREADS; i < DAEMON_THREADS + USER_THREADS_1; i++) {

            live[i] = true;

            allThreads[i] = new MyThread(i);

            allThreads[i].setDaemon(false);

            allThreads[i].start();

        }

        // wait until user1 threads have started.

        barrier.await();

        System.out.println("Number of threads added = " +

                           USER_THREADS_1);

        // Check mbean now

        if ( (!test.checkCount  (DAEMON_THREADS + USER_THREADS_1)) ||

             (!test.checkCreated(DAEMON_THREADS + USER_THREADS_1)) ||

             (!test.checkPeak   (DAEMON_THREADS + USER_THREADS_1)) ||

             (!test.checkDaemon (DAEMON_THREADS))

           )

            testFailed = true;

        // Stop daemon threads and wait to be sure they all are dead

        barrier.set(DAEMON_THREADS);

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

            live[i] = false;

        }

        // wait until daemon threads terminated.

        barrier.await();

        System.out.println("Daemon threads terminated.");

        // Check mbean now

        if ( (!test.checkCount  (USER_THREADS_1))                  ||

             (!test.checkCreated(DAEMON_THREADS + USER_THREADS_1)) ||

             (!test.checkPeak   (DAEMON_THREADS + USER_THREADS_1)) ||

             (!test.checkDaemon (0))

           )

            testFailed = true;

        // Start USER_THREADS_2 threads and wait to be sure they all are alive

        barrier.set(USER_THREADS_2);

        for (int i = DAEMON_THREADS + USER_THREADS_1; i < ALL_THREADS; i++) {

            live[i] = true;

            allThreads[i] = new MyThread(i);

            allThreads[i].setDaemon(false);

            allThreads[i].start();

        }

        // wait until user2 threads have started.

        barrier.await();

        System.out.println("Number of threads added = " +

                           USER_THREADS_2);

        // Check mbean now

        if ( (!test.checkCount  (USER_THREADS_1 + USER_THREADS_2)) ||

             (!test.checkCreated(ALL_THREADS))                     ||

             (!test.checkPeak   (DAEMON_THREADS + USER_THREADS_1)) ||

             (!test.checkDaemon (0))

           )

            testFailed = true;

        // Stop user1 threads and wait to be sure they all are dead

        barrier.set(USER_THREADS_1);

        for (int i = DAEMON_THREADS; i < DAEMON_THREADS + USER_THREADS_1; i++) {

            live[i] = false;

        }

        // wait until user1 threads terminated.

        barrier.await();

        System.out.println("Number of threads terminated = " +

                           USER_THREADS_1);

        // Check mbean now

        if ( (!test.checkCount  (USER_THREADS_2))                  ||

             (!test.checkCreated(ALL_THREADS))                     ||

             (!test.checkPeak   (DAEMON_THREADS + USER_THREADS_1)) ||

             (!test.checkDaemon (0))

           )

            testFailed = true;

        // Stop user2 threads and wait to be sure they all are dead

        barrier.set(USER_THREADS_2);

        for (int i = DAEMON_THREADS + USER_THREADS_1; i < ALL_THREADS; i++) {

            live[i] = false;

        }

        // wait until user2 threads terminated.

        barrier.await();

        System.out.println("Number of threads terminated = " +

                           USER_THREADS_2);

        // Check mbean now

        if ( (!test.checkCount  (0))                               ||

             (!test.checkCreated(ALL_THREADS))                     ||

             (!test.checkPeak   (DAEMON_THREADS + USER_THREADS_1)) ||

             (!test.checkDaemon (0))

           )

            testFailed = true;

        if (testFailed)

            throw new RuntimeException("TEST FAILED.");

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

    }

    // Nobody knows how many threads are in the JVM in the exact moment. The

    // only thing to check for sure is minimal number of threads alive (or

    // created) in the application

    private boolean checkCount(long min) {

        long result = mbean.getThreadCount();

        if (result < min) {

            System.err.println("TEST FAILED: " +

                               "Minimal number of live threads is " +

                                min +

                                ". ThreadMXBean.getThreadCount() returned " +

                                result);

            return false;

        }

        return true;

    }

    private boolean checkCreated(long min) {

        long result = mbean.getTotalStartedThreadCount();

        if (result < min) {

            System.err.println("TEST FAILED: " +

                               "Minimal number of created threads is " +

                                min +

                                ". ThreadMXBean.getTotalStartedThreadCount() "+

                                "returned " + result);

            return false;

        }

        return true;

    }

    private boolean checkPeak(long min) {

        long result = mbean.getPeakThreadCount();

        if (result < min) {

            System.err.println("TEST FAILED: " +

                               "Minimal peak thread count is " +

                                min +

                                ". ThreadMXBean.getPeakThreadCount() "+

                                "returned " + result);

            return false;

        }

        return true;

    }

    private boolean checkDaemon(long min) {

        long result = mbean.getDaemonThreadCount();

        if (result < min) {

            System.err.println("TEST FAILED: " +

                               "Minimal number of daemon thread count is " +

                                min +

                               "ThreadMXBean.getDaemonThreadCount() returned "

                                + result);

            return false;

        }

        return true;

    }

    // The MyThread thread lives as long as correspondent live[i] value is true

    private static class MyThread extends Thread {

        int id;

        MyThread(int id) {

            this.id = id;

        }

        public void run() {

            // signal started

            barrier.signal();

            while (live[id]) {

                try {

                    sleep(100);

                } catch (InterruptedException e) {

                    System.out.println("Unexpected exception is thrown.");

                    e.printStackTrace(System.out);

                    testFailed = true;

                }

            }

            // signal about to exit

            barrier.signal();

        }

    }

}