/*

 * Copyright (c) 1998, 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.  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.

 */

/*

 * This source code is provided to illustrate the usage of a given feature

 * or technique and has been deliberately simplified. Additional steps

 * required for a production-quality application, such as security checks,

 * input validation and proper error handling, might not be present in

 * this sample code.

 */

package com.sun.tools.example.debug.bdi;

import com.sun.jdi.*;

//### Should handle target VM death or connection failure cleanly.

public class ThreadInfo {

    private ThreadReference thread;

    private int status;

    private int frameCount;

    Object userObject;  // User-supplied annotation.

    private boolean interrupted = false;

    private void assureInterrupted() throws VMNotInterruptedException {

        if (!interrupted) {

            throw new VMNotInterruptedException();

        }

    }

    ThreadInfo (ThreadReference thread) {

        this.thread = thread;

        this.frameCount = -1;

    }

    public ThreadReference thread() {

        return thread;

    }

    public int getStatus() throws VMNotInterruptedException {

        assureInterrupted();

        update();

        return status;

    }

    public int getFrameCount() throws VMNotInterruptedException {

        assureInterrupted();

        update();

        return frameCount;

    }

    public StackFrame getFrame(int index) throws VMNotInterruptedException {

        assureInterrupted();

        update();

        try {

            return thread.frame(index);

        } catch (IncompatibleThreadStateException e) {

            // Should not happen

            interrupted = false;

            throw new VMNotInterruptedException();

        }

    }

    public Object getUserObject() {

        return userObject;

    }

    public void setUserObject(Object obj) {

        userObject = obj;

    }

    // Refresh upon first access after cache is cleared.

    void update() throws VMNotInterruptedException {

        if (frameCount == -1) {

            try {

                status = thread.status();

                frameCount = thread.frameCount();

            } catch (IncompatibleThreadStateException e) {

                // Should not happen

                interrupted = false;

                throw new VMNotInterruptedException();

            }

        }

    }

    // Called from 'ExecutionManager'.

    void validate() {

        interrupted = true;

    }

    void invalidate() {

        interrupted = false;

        frameCount = -1;

        status = ThreadReference.THREAD_STATUS_UNKNOWN;

    }

}