/*

 * Copyright (c) 1999, 2000, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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 sun.awt;

public class Mutex {

    private boolean locked;

    private Thread owner;

    public synchronized void lock() {

        if (locked && Thread.currentThread() == owner) {

            throw new IllegalMonitorStateException();

        }

        do {

            if (!locked) {

                locked = true;

                owner = Thread.currentThread();

            } else {

                try {

                    wait();

                } catch (InterruptedException e) {

                    // try again

                }

            }

        } while (owner != Thread.currentThread());

    }

    public synchronized void unlock() {

        if (Thread.currentThread() != owner) {

            throw new IllegalMonitorStateException();

        }

        owner = null;

        locked = false;

        notify();

    }

    protected boolean isOwned() {

        return (locked && Thread.currentThread() == owner);

    }

}