/*

 * Copyright (c) 2005, 2008, 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 com.sun.tools.jdi;

import com.sun.jdi.*;

public class MonitorInfoImpl extends MirrorImpl

    implements MonitorInfo, ThreadListener {

    /* Once false, monitorInfo should not be used.

     * access synchronized on (vm.state())

     */

    private boolean isValid = true;

    ObjectReference monitor;

    ThreadReference thread;

    int  stack_depth;

    MonitorInfoImpl(VirtualMachine vm, ObjectReference mon,

                    ThreadReferenceImpl thread, int dpth) {

        super(vm);

        this.monitor = mon;

        this.thread = thread;

        this.stack_depth = dpth;

        thread.addListener(this);

    }

    /*

     * ThreadListener implementation

     * Must be synchronized since we must protect against

     * sending defunct (isValid == false) stack ids to the back-end.

     */

    public boolean threadResumable(ThreadAction action) {

        synchronized (vm.state()) {

            if (isValid) {

                isValid = false;

                return false;   /* remove this stack frame as a listener */

            } else {

                throw new InternalException(

                                  "Invalid stack frame thread listener");

            }

        }

    }

    private void validateMonitorInfo() {

        if (!isValid) {

            throw new InvalidStackFrameException("Thread has been resumed");

        }

    }

    public ObjectReference monitor() {

        validateMonitorInfo();

        return monitor;

    }

    public int stackDepth() {

        validateMonitorInfo();

        return stack_depth;

    }

    public ThreadReference thread() {

        validateMonitorInfo();

        return thread;

    }

}