/*

 * Copyright (c) 2013 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 7105883

 *  @summary Ensure that JDWP doesn't crash with a null thread group name

 *

 *  @run build TestScaffold VMConnection TargetListener TargetAdapter

 *  @run main NullThreadGroupNameTest

 */

import com.sun.jdi.*;

import com.sun.jdi.connect.*;

import com.sun.jdi.event.*;

import com.sun.jdi.request.*;

import com.sun.jdi.VMDisconnectedException;

import java.util.concurrent.CountDownLatch;

import java.util.*;

class DebugTarget {

    public final static String DEBUG_THREAD_NAME = "DebugThread";

    public static void main(String[] args) throws Exception {

        DebugThread thread = new DebugThread();

        thread.start();

        thread.runningLatch.await();

        breakpointHere();

        thread.breakpointLatch.countDown();

    }

    public static void breakpointHere() {

        System.out.println("Breakpoint finished!");

    }

    static class DebugThread extends Thread {

        final CountDownLatch runningLatch = new CountDownLatch(1);

        final CountDownLatch breakpointLatch = new CountDownLatch(1);

        public DebugThread() {

            super(new ThreadGroup(null), DEBUG_THREAD_NAME);

        }

        public void run() {

            runningLatch.countDown();

            try {

                breakpointLatch.await();

            } catch (InterruptedException ie) {

                ie.printStackTrace();

            }

        }

    }

}

public class NullThreadGroupNameTest extends TestScaffold {

    NullThreadGroupNameTest(String args[]) {

        super(args);

    }

    public static void main(String[] args) throws Exception {

        new NullThreadGroupNameTest(args).startTests();

    }

    protected void runTests() throws Exception {

        startTo("DebugTarget", "breakpointHere", "()V");

        ThreadReference thread = findThread(DebugTarget.DEBUG_THREAD_NAME);

        assertThreadGroupName(thread.threadGroup(), "");

        listenUntilVMDisconnect();

    }

    private ThreadReference findThread(String name) {

        for (ThreadReference thread : vm().allThreads()) {

            if (name.equals(thread.name())) {

                return thread;

            }

        }

        throw new NoSuchElementException("Couldn't find " + name);

    }

    private void assertThreadGroupName(ThreadGroupReference threadGroup, String expectedName) {

        try {

            String name = threadGroup.name();

            if (!expectedName.equals(name)) {

                throw new AssertionError("Unexpected thread group name '" + name + "'");

            }

        } catch (VMDisconnectedException vmde) {

            throw new AssertionError("Likely JVM crash with null thread group name", vmde);

        }

    }

}