/*

 * Copyright (c) 2004, 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

 * @bug     5014783

 * @summary Basic unit test of thread states returned by

 *          Thread.getState().

 *

 * @author  Mandy Chung

 *

 * @build ThreadStateTest

 */

import java.util.concurrent.locks.LockSupport;

import java.util.concurrent.Phaser;

public class ThreadStateTest {

    // maximum number of retries when checking for thread state.

    static final int MAX_RETRY = 500;

    private static boolean testFailed = false;

    // used to achieve waiting states

    static final Object globalLock = new Object();

    public static void main(String[] argv) {

        // Call Thread.getState to force all initialization done

        // before test verification begins.

        Thread.currentThread().getState();

        MyThread myThread = new MyThread("MyThread");

        // before myThread starts

        checkThreadState(myThread, Thread.State.NEW);

        myThread.start();

        myThread.waitUntilStarted();

        checkThreadState(myThread, Thread.State.RUNNABLE);

        synchronized (globalLock) {

            myThread.goBlocked();

            checkThreadState(myThread, Thread.State.BLOCKED);

        }

        myThread.goWaiting();

        checkThreadState(myThread, Thread.State.WAITING);

        myThread.goTimedWaiting();

        checkThreadState(myThread, Thread.State.TIMED_WAITING);

      /*

       *********** park and parkUntil seems not working

       * ignore this case for now.

       * Bug ID 5062095

       ***********************************************

        myThread.goParked();

        checkThreadState(myThread, Thread.State.WAITING);

        myThread.goTimedParked();

        checkThreadState(myThread, Thread.State.TIMED_WAITING);

       */

        myThread.goSleeping();

        checkThreadState(myThread, Thread.State.TIMED_WAITING);

        myThread.terminate();

        checkThreadState(myThread, Thread.State.TERMINATED);

        try {

            myThread.join();

        } catch (InterruptedException e) {

            e.printStackTrace();

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

            testFailed = true;

        }

        if (testFailed)

            throw new RuntimeException("TEST FAILED.");

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

    }

    private static void checkThreadState(Thread t, Thread.State expected) {

        // wait for the thread to transition to the expected state.

        // There is a small window between the thread checking the state

        // and the thread actual entering that state.

        Thread.State state;

        int retryCount=0;

        while ((state = t.getState()) != expected && retryCount < MAX_RETRY) {

            if (state != Thread.State.RUNNABLE) {

                throw new RuntimeException("Thread not in expected state yet," +

                        " but it should at least be RUNNABLE");

            }

            goSleep(10);

            retryCount++;

        }

        System.out.println("Checking thread state " + state);

        if (state == null) {

            throw new RuntimeException(t.getName() + " expected to have " +

                expected + " but got null.");

        }

        if (state != expected) {

            throw new RuntimeException(t.getName() + " expected to have " +

                expected + " but got " + state);

        }

    }

    private static void goSleep(long ms) {

        try {

            Thread.sleep(ms);

        } catch (InterruptedException e) {

            e.printStackTrace();

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

            testFailed = true;

        }

    }

    static class MyThread extends Thread {

        // Phaser to sync between the main thread putting

        // this thread into various states

        private Phaser phaser =  new Phaser(2);

        MyThread(String name) {

            super(name);

        }

        private final int RUNNABLE = 0;

        private final int BLOCKED = 1;

        private final int WAITING = 2;

        private final int TIMED_WAITING = 3;

        private final int PARKED = 4;

        private final int TIMED_PARKED = 5;

        private final int SLEEPING = 6;

        private final int TERMINATE = 7;

        private volatile int state = RUNNABLE;

        private boolean done = false;

        public void run() {

            // Signal main thread to continue.

            phaser.arriveAndAwaitAdvance();

            while (!done) {

                switch (state) {

                    case RUNNABLE: {

                        double sum = 0;

                        for (int i = 0; i < 1000; i++) {

                           double r = Math.random();

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

                           sum += x - r;

                        }

                        break;

                    }

                    case BLOCKED: {

                        // signal main thread.

                        phaser.arrive();

                        System.out.println("  myThread is going to block.");

                        synchronized (globalLock) {

                            // finish blocking

                            state = RUNNABLE;

                        }

                        break;

                    }

                    case WAITING: {

                        synchronized (globalLock) {

                            // signal main thread.

                            phaser.arrive();

                            System.out.println("  myThread is going to wait.");

                            try {

                                globalLock.wait();

                            } catch (InterruptedException e) {

                                // ignore

                            }

                        }

                        break;

                    }

                    case TIMED_WAITING: {

                        synchronized (globalLock) {

                            // signal main thread.

                            phaser.arrive();

                            System.out.println("  myThread is going to timed wait.");

                            try {

                                globalLock.wait(10000);

                            } catch (InterruptedException e) {

                                // ignore

                            }

                        }

                        break;

                    }

                    case PARKED: {

                        // signal main thread.

                        phaser.arrive();

                        System.out.println("  myThread is going to park.");

                        LockSupport.park();

                        // give a chance for the main thread to block

                        goSleep(10);

                        break;

                    }

                    case TIMED_PARKED: {

                        // signal main thread.

                        phaser.arrive();

                        System.out.println("  myThread is going to timed park.");

                        long deadline = System.currentTimeMillis() + 10000*1000;

                        LockSupport.parkUntil(deadline);

                        // give a chance for the main thread to block

                        goSleep(10);

                        break;

                    }

                    case SLEEPING: {

                        // signal main thread.

                        phaser.arrive();

                        System.out.println("  myThread is going to sleep.");

                        try {

                            Thread.sleep(1000000);

                        } catch (InterruptedException e) {

                            // finish sleeping

                        }

                        break;

                    }

                    case TERMINATE: {

                        done = true;

                        // signal main thread.

                        phaser.arrive();

                        break;

                    }

                    default:

                        break;

                }

            }

        }

        public void waitUntilStarted() {

            // wait for MyThread.

            phaser.arriveAndAwaitAdvance();

        }

        public void goBlocked() {

            System.out.println("Waiting myThread to go blocked.");

            setState(BLOCKED);

            // wait for MyThread to get to a point just before being blocked

            phaser.arriveAndAwaitAdvance();

        }

        public void goWaiting() {

            System.out.println("Waiting myThread to go waiting.");

            setState(WAITING);

            // wait for MyThread to get to just before wait on object.

            phaser.arriveAndAwaitAdvance();

        }

        public void goTimedWaiting() {

            System.out.println("Waiting myThread to go timed waiting.");

            setState(TIMED_WAITING);

            // wait for MyThread to get to just before timed wait call.

            phaser.arriveAndAwaitAdvance();

        }

        public void goParked() {

            System.out.println("Waiting myThread to go parked.");

            setState(PARKED);

            // wait for MyThread to get to just before parked.

            phaser.arriveAndAwaitAdvance();

        }

        public void goTimedParked() {

            System.out.println("Waiting myThread to go timed parked.");

            setState(TIMED_PARKED);

            // wait for MyThread to get to just before timed park.

            phaser.arriveAndAwaitAdvance();

        }

        public void goSleeping() {

            System.out.println("Waiting myThread to go sleeping.");

            setState(SLEEPING);

            // wait for MyThread to get to just before sleeping

            phaser.arriveAndAwaitAdvance();

        }

        public void terminate() {

            System.out.println("Waiting myThread to terminate.");

            setState(TERMINATE);

            // wait for MyThread to get to just before terminate

            phaser.arriveAndAwaitAdvance();

        }

        private void setState(int newState) {

            switch (state) {

                case BLOCKED:

                    while (state == BLOCKED) {

                        goSleep(10);

                    }

                    state = newState;

                    break;

                case WAITING:

                case TIMED_WAITING:

                    state = newState;

                    synchronized (globalLock) {

                        globalLock.notify();

                    }

                    break;

                case PARKED:

                case TIMED_PARKED:

                    state = newState;

                    LockSupport.unpark(this);

                    break;

                case SLEEPING:

                    state = newState;

                    this.interrupt();

                    break;

                default:

                    state = newState;

                    break;

            }

        }

    }

}