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/*

 * @test

 * @bug     6173675

 * @summary Basic test of ThreadMXBean.getThreadCpuTime(long[]) and

 *          getThreadUserTime(long[]).

 * @author  Paul Hohensee

 * @key randomness

 */

import java.lang.management.*;

public class ThreadCpuTimeArray {

    private static com.sun.management.ThreadMXBean mbean =

        (com.sun.management.ThreadMXBean)ManagementFactory.getThreadMXBean();

    private static boolean testFailed = false;

    private static boolean done = false;

    private static Object obj = new Object();

    private static final int NUM_THREADS = 10;

    private static Thread[] threads = new Thread[NUM_THREADS];

    // careful about this value

    private static final int DELTA = 100;

    public static void main(String[] argv)

        throws Exception {

        if (!mbean.isThreadCpuTimeSupported()) {

            return;

        }

        // disable CPU time

        if (mbean.isThreadCpuTimeEnabled()) {

            mbean.setThreadCpuTimeEnabled(false);

        }

        if (mbean.isThreadCpuTimeEnabled()) {

            throw new RuntimeException("ThreadCpuTime is expected to be disabled");

        }

        // start threads, wait for them to block

        long[] ids = new long[NUM_THREADS];

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

            threads[i] = new MyThread("MyThread-" + i);

            threads[i].start();

            ids[i] = threads[i].getId();

        }

        // threads block after doing some computation

        waitUntilThreadBlocked();

        long times[] = mbean.getThreadCpuTime(ids);

        long userTimes[] = mbean.getThreadUserTime(ids);

        if (times == null) {

            throw new RuntimeException("Null ThreadCpuTime array returned");

        }

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

            long t = times[i];

            if (t != -1) {

                throw new RuntimeException(

                    "Invalid ThreadCpuTime returned for thread " +

                    threads[i].getName() + " = " +  t + " expected = -1");

            }

            long ut = userTimes[i];

            if (ut != -1) {

                throw new RuntimeException(

                    "Invalid ThreadUserTime returned for thread " +

                    threads[i].getName() + " = " +  ut + " expected = -1");

            }

        }

        // Enable CPU Time measurement

        if (!mbean.isThreadCpuTimeEnabled()) {

            mbean.setThreadCpuTimeEnabled(true);

        }

        if (!mbean.isThreadCpuTimeEnabled()) {

            throw new RuntimeException("ThreadCpuTime is expected to be enabled");

        }

        times = mbean.getThreadCpuTime(ids);

        userTimes = mbean.getThreadUserTime(ids);

        goSleep(200);

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

            long t = times[i];

            if (t < 0) {

                throw new RuntimeException(

                    "Invalid CPU time returned for thread " +

                    threads[i].getName() + " = " + t);

            }

            long ut = userTimes[i];

            if (ut < 0) {

                throw new RuntimeException(

                    "Invalid user time returned for thread " +

                    threads[i].getName() + " = " + ut);

            }

        }

        long[] times1 = mbean.getThreadCpuTime(ids);

        long[] userTimes1 = mbean.getThreadUserTime(ids);

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

            long newTime = times1[i];

            long newUserTime = userTimes1[i];

            if (times[i] > newTime) {

                throw new RuntimeException("TEST FAILED: " +

                    threads[i].getName() +

                    " previous CPU time = " + times[i] +

                    " > current CPU time = " + newTime);

            }

            if ((times[i] + DELTA) < newTime) {

                throw new RuntimeException("TEST FAILED: " +

                    threads[i].getName() +

                    " CPU time = " + newTime +

                    " previous CPU time " + times[i] +

                    " out of expected range");

            }

            System.out.println(threads[i].getName() +

                " Previous Cpu Time = " + times[i] +

                " Current CPU time = " + newTime);

            System.out.println(threads[i].getName() +

                " Previous User Time = " + userTimes[i] +

                " Current User time = " + newUserTime);

        }

        try {

            times = mbean.getThreadCpuTime(null);

        } catch (NullPointerException e) {

            System.out.println(

                "Caught expected NullPointerException: " + e.getMessage());

        }

        try {

            ids[0] = 0;

            times = mbean.getThreadCpuTime(ids);

        } catch (IllegalArgumentException e) {

            System.out.println(

                "Caught expected IllegalArgumentException: " + e.getMessage());

        }

        // let threads exit

        synchronized (obj) {

            done = true;

            obj.notifyAll();

        }

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

            try {

                threads[i].join();

            } catch (InterruptedException e) {

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

                e.printStackTrace(System.out);

                testFailed = true;

                break;

            }

        }

        if (testFailed) {

            throw new RuntimeException("TEST FAILED");

        }

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

    }

    private static void goSleep(long ms) throws Exception {

        try {

            Thread.sleep(ms);

        } catch (InterruptedException e) {

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

            throw e;

        }

    }

    private static void waitUntilThreadBlocked()

        throws Exception {

        int count = 0;

        while (count != NUM_THREADS) {

            goSleep(100);

            count = 0;

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

                ThreadInfo info = mbean.getThreadInfo(threads[i].getId());

                if (info.getThreadState() == Thread.State.WAITING) {

                    count++;

                }

            }

        }

    }

    public static void doit() {

        double sum = 0;

        for (int i = 0; i < 5000; i++) {

           double r = Math.random();

           double x = Math.pow(3, r);

           sum += x - r;

        }

        System.out.println(Thread.currentThread().getName() +

                           " sum = " + sum);

    }

    static class MyThread extends Thread {

        public MyThread(String name) {

            super(name);

        }

        public void run() {

            ThreadCpuTimeArray.doit();

            synchronized (obj) {

                while (!done) {

                    try {

                        obj.wait();

                    } catch (InterruptedException e) {

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

                        e.printStackTrace(System.out);

                        testFailed = true;

                        break;

                    }

                }

            }

            ThreadCpuTimeArray.doit();

        }

    }

}