/*

 * Copyright (c) 2006, 2018, 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.

 */

package nsk.share.jpda;

import nsk.share.TestBug;

import nsk.share.locks.MonitorLockingThread;

/*

 *  StateTestThread sequentially switches its state in following order:

 *  - thread not started

 *  - thread is running

 *  - thread is sleeping

 *  - thread in Object.wait()

 *  - thread wait on java monitor

 *  - thread is finished

 *

 *  To use this class create new instance of StateTestThread and sequentially call method nextState().

 */

public class StateTestThread extends Thread {

    // thread states available through ThreadReference.state()

    public static String stateTestThreadStates[] = { "UNKNOWN", "RUNNING", "SLEEPING", "WAIT", "MONITOR", "ZOMBIE" };

    private Object waitOnObject = new Object();

    public StateTestThread(String name) {

        super(name);

    }

    private volatile boolean isRunning;

    private volatile boolean waitState;

    public int getCurrentState() {

        return currentState;

    }

    private MonitorLockingThread auxiliaryThread = new MonitorLockingThread(this);

    private boolean isExecutedWithErrors;

    private volatile boolean readyToBeBlocked;

    private String errorMessage;

    public void run() {

        isRunning = true;

        // running state

        while (isRunning)

            ;

        try {

            // sleeping state

            sleep(Long.MAX_VALUE);

        } catch (InterruptedException e) {

            // expected exception

        }

        synchronized (waitOnObject) {

            try {

                // wait state

                while (waitState)

                    waitOnObject.wait();

            } catch (InterruptedException e) {

                isExecutedWithErrors = true;

                errorMessage = "StateTestThread was unexpected interrupted during waiting";

            }

        }

        // start auxiliary thread which should acquire 'this' lock

        auxiliaryThread.acquireLock();

        readyToBeBlocked = true;

        // try acquire the same lock as auxiliaryThread, switch state to 'wait on monitor'

        synchronized (this) {

        }

    }

    private int currentState = 1;

    public void nextState() {

        // check is thread states change as expected

        if (isExecutedWithErrors)

            throw new TestBug(errorMessage);

        switch (currentState++) {

        case 1:

            // start thread

            start();

            while (!isRunning)

            break;

        case 2:

            // stop running

            isRunning = false;

            while (this.getState() != Thread.State.TIMED_WAITING)

            break;

        case 3:

            waitState = true;

            // stop sleeping

            interrupt();

            while (getState() != Thread.State.WAITING)

            break;

        case 4:

            waitState = false;

            // stop wait

            synchronized (waitOnObject) {

                waitOnObject.notify();

            }

            while (!readyToBeBlocked || (getState() != Thread.State.BLOCKED))

            break;

        case 5:

            // let StateTestThread thread acquire lock

            auxiliaryThread.releaseLock();

            try {

                join();

            } catch (InterruptedException e) {

                throw new TestBug("Unexpected exception: " + e);

            }

            break;

        default:

            throw new TestBug("Invalid thread state");

        }

    }

}