CounterMonitorDeadlockTest.java 文件源码

void run() throws Exception {
    final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
    final ObjectName observedName = new ObjectName("a:b=c");
    final ObjectName monitorName = new ObjectName("a:type=Monitor");
    mbs.registerMBean(new CounterMonitor(), monitorName);
    final CounterMonitorMBean monitorProxy =
        JMX.newMBeanProxy(mbs, monitorName, CounterMonitorMBean.class);
    final TestMBean observedProxy =
        JMX.newMBeanProxy(mbs, observedName, TestMBean.class);

    final Runnable sensitiveThing = new Runnable() {
        public void run() {
            doSensitiveThing(monitorProxy, observedName);
        }
    };

    final Runnable nothing = new Runnable() {
        public void run() {}
    };

    final Runnable withinGetAttribute =
        (when == When.IN_GET_ATTRIBUTE) ? sensitiveThing : nothing;

    mbs.registerMBean(new Test(withinGetAttribute), observedName);
    monitorProxy.addObservedObject(observedName);
    monitorProxy.setObservedAttribute("Thing");
    monitorProxy.setInitThreshold(100);
    monitorProxy.setGranularityPeriod(10L); // 10 ms
    monitorProxy.setNotify(true);

    final int initGetCount = observedProxy.getGetCount();
    monitorProxy.start();

    System.out.println("Checking GetCount, possible deadlock if timeout.");
    do { // 8038322. Until timeout of testing harness
        Thread.sleep(200);
    } while ((observedProxy.getGetCount()) == initGetCount);
    System.out.println("Done!");

    // This won't show up as a deadlock in CTRL-\ or in
    // ThreadMXBean.findDeadlockedThreads(), because they don't
    // see that thread A is waiting for thread B (B.join()), and
    // thread B is waiting for a lock held by thread A

    // Now we know the monitor has observed the initial value,
    // so if we want to test notify behaviour we can trigger by
    // exceeding the threshold.
    if (when == When.IN_NOTIFY) {
        final AtomicInteger notifCount = new AtomicInteger();
        final NotificationListener listener = new NotificationListener() {
            public void handleNotification(Notification n, Object h) {
                Thread t = new Thread(sensitiveThing);
                t.start();
                try {
                    t.join();
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
                notifCount.incrementAndGet();
            }
        };
        mbs.addNotificationListener(monitorName, listener, null, null);
        observedProxy.setThing(1000);
        System.out.println("Waiting notifCount.get() != 0, possible deadlock if timeout.");
        do {
            Thread.sleep(200);
        } while(notifCount.get() == 0); // 8038322. Until timeout of testing harness
        System.out.println("Done");
    }

}