Java example source code file (SuspendThreadTest.java)

This example Java source code file (SuspendThreadTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

breakpointrequest, classtype, could, exception, field, got, interruptedexception, jdi, location, longvalue, suspendthreadtarg, suspendthreadtest, testscaffold, threadreference, util, vmdisconnectevent

The SuspendThreadTest.java Java example source code

/*
 * Copyright (c) 2006, 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 6485605
 *  @summary com.sun.jdi.InternalException: Inconsistent suspend policy in internal event handler
 *
 *  @author jjh
 *
 *  @run build TestScaffold VMConnection TargetListener TargetAdapter
 *  @run compile -g SuspendThreadTest.java
 *  @run main SuspendThreadTest
 */
import com.sun.jdi.*;
import com.sun.jdi.event.*;
import com.sun.jdi.request.*;

import java.util.*;

    /********** target program **********/

class SuspendThreadTarg {
    public static long count;

    public static void bkpt() {
        count++;
    }

    public static void main(String[] args){
        System.out.println("Howdy!");

        // We need this to be running so the bkpt
        // can be hit immediately when it is enabled
        // in the back-end.
        while(count >= 0) {
            bkpt();
        }
        System.out.println("Goodbye from SuspendThreadTarg, count = " + count);
    }
}

    /********** test program **********/

public class SuspendThreadTest extends TestScaffold {
    ClassType targetClass;
    ThreadReference mainThread;

    SuspendThreadTest (String args[]) {
        super(args);
    }

    public static void main(String[] args)      throws Exception {
        new SuspendThreadTest(args).startTests();
    }

    /********** event handlers **********/

    // 1000 makes the test take over 2 mins on win32
    static int maxBkpts = 200;
    int bkptCount;
    BreakpointRequest bkptRequest;
    Field debuggeeCountField;

    // When we get a bkpt we want to disable the request,
    // resume the debuggee, and then re-enable the request
    public void breakpointReached(BreakpointEvent event) {
        System.out.println("Got BreakpointEvent: " + bkptCount +
                           ", debuggeeCount = " +
                           ((LongValue)targetClass.
                            getValue(debuggeeCountField)).value()
                           );
        bkptRequest.disable();
    }

    public void eventSetComplete(EventSet set) {
        set.resume();

        // The main thread watchs the bkptCount to
        // see if bkpts stop coming in.  The
        // test _should_ fail well before maxBkpts bkpts.
        if (bkptCount++ < maxBkpts) {
            bkptRequest.enable();
        }
    }

    public void vmDisconnected(VMDisconnectEvent event) {
        println("Got VMDisconnectEvent");
    }

    /********** test core **********/

    protected void runTests() throws Exception {
        /*
         * Get to the top of main()
         * to determine targetClass and mainThread
         */
        BreakpointEvent bpe = startToMain("SuspendThreadTarg");
        targetClass = (ClassType)bpe.location().declaringType();
        mainThread = bpe.thread();
        EventRequestManager erm = vm().eventRequestManager();

        Location loc1 = findMethod(targetClass, "bkpt", "()V").location();

        bkptRequest = erm.createBreakpointRequest(loc1);

        // Without this, it is a SUSPEND_ALL bkpt and the test will pass
        bkptRequest.setSuspendPolicy(EventRequest.SUSPEND_EVENT_THREAD);
        bkptRequest.enable();

        debuggeeCountField = targetClass.fieldByName("count");
        try {

            addListener (this);
        } catch (Exception ex){
            ex.printStackTrace();
            failure("failure: Could not add listener");
            throw new Exception("SuspendThreadTest: failed");
        }

        int prevBkptCount;
        vm().resume();
        while (bkptCount < maxBkpts) {
            prevBkptCount = bkptCount;
            // If we don't get a bkpt within 5 secs,
            // the test fails
            try {
                Thread.sleep(5000);
            } catch (InterruptedException ee) {
            }
            if (prevBkptCount == bkptCount) {
                failure("failure: test hung");
                break;
            }
            prevBkptCount = bkptCount;
        }
        println("done with loop");
        bkptRequest.disable();
        removeListener(this);


        /*
         * deal with results of test
         * if anything has called failure("foo") testFailed will be true
         */
        if (!testFailed) {
            println("SuspendThreadTest: passed");
        } else {
            throw new Exception("SuspendThreadTest: failed");
        }
    }
}