Java NotificationEmitter类代码示例

import javax.management.NotificationEmitter; //导入依赖的package包/类
private static void installGCMonitoring() {
    List<GarbageCollectorMXBean> gcbeans = java.lang.management.ManagementFactory.getGarbageCollectorMXBeans();
    for (GarbageCollectorMXBean gcbean : gcbeans) {
        NotificationEmitter emitter = (NotificationEmitter) gcbean;
        System.out.println(gcbean.getName());

        NotificationListener listener = (notification, handback) -> {
            if (notification.getType().equals(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION)) {
                GarbageCollectionNotificationInfo info = GarbageCollectionNotificationInfo.from((CompositeData) notification.getUserData());

                long duration = info.getGcInfo().getDuration();
                String gctype = info.getGcAction();

                System.out.println(gctype + ": - "
                        + info.getGcInfo().getId() + ", "
                        + info.getGcName()
                        + " (from " + info.getGcCause() + ") " + duration + " milliseconds");

            }
        };

        emitter.addNotificationListener(listener, null, null);
    }
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
/**
 * Register with the JVM to get threshold events.
 * 
 * Package private for testing.
 */
void startJVMThresholdListener() {
  final MemoryPoolMXBean memoryPoolMXBean = getTenuredMemoryPoolMXBean();

  // Set collection threshold to a low value, so that we can get
  // notifications after every GC run. After each such collection
  // threshold notification we set the usage thresholds to an
  // appropriate value.
  if (!testDisableMemoryUpdates) {
    memoryPoolMXBean.setCollectionUsageThreshold(1);
  }

  final long usageThreshold = memoryPoolMXBean.getUsageThreshold();
  this.cache.getLoggerI18n().info(
      LocalizedStrings.HeapMemoryMonitor_OVERRIDDING_MEMORYPOOLMXBEAN_HEAP_0_NAME_1,
      new Object[] {Long.valueOf(usageThreshold), memoryPoolMXBean.getName()});

  MemoryMXBean mbean = ManagementFactory.getMemoryMXBean();
  NotificationEmitter emitter = (NotificationEmitter) mbean;
  emitter.addNotificationListener(this, null, null);
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
/**
 * Transfroms a proxy implementing T in a proxy implementing T plus
 * NotificationEmitter
 *
 **/
public static <T> T makeNotificationEmitter(T proxy,
                    Class<T> mbeanInterface) {
    if (proxy instanceof NotificationEmitter)
        return proxy;
    if (proxy == null) return null;
    if (!(proxy instanceof Proxy))
        throw new IllegalArgumentException("not a "+Proxy.class.getName());
    final Proxy p = (Proxy) proxy;
    final InvocationHandler handler =
            Proxy.getInvocationHandler(proxy);
    if (!(handler instanceof MBeanServerInvocationHandler))
        throw new IllegalArgumentException("not a JMX Proxy");
    final MBeanServerInvocationHandler h =
            (MBeanServerInvocationHandler)handler;
    final ObjectName name = h.getObjectName();
    final MBeanServerConnection mbs = h.getMBeanServerConnection();
    final boolean isMXBean = h.isMXBean();
    final T newProxy;
    if (isMXBean)
        newProxy = JMX.newMXBeanProxy(mbs,name,mbeanInterface,true);
    else
        newProxy = JMX.newMBeanProxy(mbs,name,mbeanInterface,true);
    return newProxy;
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
protected void runTest() {
    int iterationsCount
            = Integer.getInteger("jdk.test.lib.iterations", 1);
    MemoryPoolMXBean bean = btype.getMemoryPool();
    ((NotificationEmitter) ManagementFactory.getMemoryMXBean()).
            addNotificationListener(this, null, null);
    for (int i = 0; i < iterationsCount; i++) {
        CodeCacheUtils.hitUsageThreshold(bean, btype);
    }
    Asserts.assertTrue(
            Utils.waitForCondition(
                    () -> (CodeCacheUtils.isCodeHeapPredictable(btype) ?
                            (counter == iterationsCount) : (counter >= iterationsCount)),
                    WAIT_TIME),
            "Couldn't receive expected notifications count");
    try {
        ((NotificationEmitter) ManagementFactory.getMemoryMXBean()).
                removeNotificationListener(this);
    } catch (ListenerNotFoundException ex) {
        throw new AssertionError("Can't remove notification listener", ex);
    }
    System.out.printf("INFO: Scenario finished successfully for %s%n",
            bean.getName());
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
protected void runTest() {
    int iterationsCount =
        Integer.getInteger("jdk.test.lib.iterations", 1);
    MemoryPoolMXBean bean = btype.getMemoryPool();
    ((NotificationEmitter) ManagementFactory.getMemoryMXBean()).
            addNotificationListener(this, null, null);
    for (int i = 0; i < iterationsCount; i++) {
        CodeCacheUtils.hitUsageThreshold(bean, btype);
    }
    Asserts.assertTrue(
            Utils.waitForCondition(
                    () -> (CodeCacheUtils.isCodeHeapPredictable(btype) ?
                            (counter == iterationsCount) : (counter >= iterationsCount)),
                    WAIT_TIME),
            "Couldn't receive expected notifications count");
    try {
        ((NotificationEmitter) ManagementFactory.getMemoryMXBean()).
                removeNotificationListener(this);
    } catch (ListenerNotFoundException ex) {
        throw new AssertionError("Can't remove notification listener", ex);
    }
    System.out.printf("INFO: Scenario finished successfully for %s%n",
            bean.getName());
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
public MemoryMonitor() {
    LOG.info("initializing");
    this.springContextId = "Unknown";
    MemoryMXBean mbean = ManagementFactory.getMemoryMXBean();
    NotificationEmitter emitter = (NotificationEmitter) mbean;
    emitter.addNotificationListener(new NotificationListener() {
        public void handleNotification(Notification n, Object hb) {
            if (n.getType().equals(MemoryNotificationInfo.MEMORY_THRESHOLD_EXCEEDED)) {
                long maxMemory = tenuredGenPool.getUsage().getMax();
                long usedMemory = tenuredGenPool.getUsage().getUsed();
                for (Listener listener : listeners) {
                    listener.memoryUsageLow(springContextId, usedMemory, maxMemory);
                }
            }
        }
    }, null, null);
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
public static void setUpGCMonitoring() {
  for (java.lang.management.GarbageCollectorMXBean bean : gcbeans) {
    NotificationEmitter emitter = (NotificationEmitter) bean;
    NotificationListener listener = new NotificationListener() {
      @Override
      public void handleNotification(final Notification notification,
          final Object handback) {
        if (GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION.equals(
            notification.getType())) {
          GarbageCollectionNotificationInfo info = GarbageCollectionNotificationInfo.from(
              (CompositeData) notification.getUserData());
          long after = getTotal(info.getGcInfo().getMemoryUsageAfterGc());
          long before = getTotal(info.getGcInfo().getMemoryUsageBeforeGc());
          collectedMemory += before - after;
        }
      }
    };
    emitter.addNotificationListener(listener, null, null);
  }
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
public synchronized static void init(ConfigServer cs){
      if(init) return;
		// set level
      for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) {
    	  types.put(pool.getName(), pool.getType());
        // I don't know whether this approach is better, or whether
        // we should rather check for the pool name "Tenured Gen"?
    	  if (pool.getType() == MemoryType.HEAP && pool.isUsageThresholdSupported()) {
    		  long maxMemory = pool.getUsage().getMax();
    		  long warningThreshold = (long) (maxMemory * 0.9);
    		  //long warningThreshold = maxMemory -(10*1024*1024);
    		  pool.setUsageThreshold(warningThreshold);
    	  }
      }
      
      MemoryMXBean mbean = ManagementFactory.getMemoryMXBean();
      NotificationEmitter emitter = (NotificationEmitter) mbean;
      MemoryNotificationListener listener = new MemoryNotificationListener(types);
      emitter.addNotificationListener(listener, null, cs);
      init=true;
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
public MemoryMonitor() {
    LOG.info("initializing");
    this.springContextId = "Unknown";
    ManagementFactory.getThreadMXBean().setThreadContentionMonitoringEnabled(true);
    ManagementFactory.getThreadMXBean().setThreadCpuTimeEnabled(true);
    lowMemoryListener = new NotificationListener() {
        public void handleNotification(Notification n, Object hb) {
            if (n.getType().equals(MemoryNotificationInfo.MEMORY_THRESHOLD_EXCEEDED)) {
                Map<String, String> memoryUsageStatistics = new HashMap<String, String>();
                memoryUsageStatistics.put("MemoryMXBean: " + MemoryType.HEAP, ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().toString());
                memoryUsageStatistics.put("MemoryMXBean:" + MemoryType.NON_HEAP, ManagementFactory.getMemoryMXBean().getNonHeapMemoryUsage().toString());
                for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) {
                    memoryUsageStatistics.put("MemoryPoolMXBean: " + pool.getType(), pool.getUsage().toString());
                }
                for (Listener listener : listeners) {
                    listener.memoryUsageLow(springContextId, memoryUsageStatistics, Arrays.toString(ManagementFactory.getThreadMXBean().findMonitorDeadlockedThreads()));
                }
            }
        }
    };
    ((NotificationEmitter) ManagementFactory.getMemoryMXBean()).addNotificationListener(lowMemoryListener, null, null);
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
/**
 * Start collecting data about GC events.
 *
 * @param listener
 *     If not null, the listener will be called with the event objects after metrics and the
 *     log buffer is updated.
 */
public synchronized void start(GcEventListener listener) {
  // TODO: this class has a bad mix of static fields used from an instance of the class. For now
  // this has been changed not to throw to make the dependency injection use-cases work. A
  // more general refactor of the GcLogger class is needed.
  if (notifListener != null) {
    LOGGER.warn("logger already started");
    return;
  }
  eventListener = listener;
  notifListener = new GcNotificationListener();
  for (GarbageCollectorMXBean mbean : ManagementFactory.getGarbageCollectorMXBeans()) {
    if (mbean instanceof NotificationEmitter) {
      final NotificationEmitter emitter = (NotificationEmitter) mbean;
      emitter.addNotificationListener(notifListener, null, null);
    }
  }
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
/**
 * @param <T>
 * @param connection
 * @param mxbeanName
 * @param mxbeanInterface
 * @return a new proxy object representing the named <code>MXBean</code>.
 *         All subsequent method invocations on the proxy will be routed
 *         through the supplied {@link MBeanServerConnection} object.
 * @throws IOException
 */
@SuppressWarnings("unchecked")
public static <T> T newPlatformMXBeanProxy(MBeanServerConnection connection,
        String mxbeanName, Class<T> mxbeanInterface) throws IOException {
    // Check that the named object implements the specified interface
    verifyNamedMXBean(mxbeanName, mxbeanInterface);

    T result = null;
    Class[] interfaces = null;
    if (ManagementUtils.isANotificationEmitter(mxbeanInterface)) {
        // Proxies of the MemoryMXBean and OperatingSystemMXBean interfaces
        // must also implement the NotificationEmitter interface.
        interfaces = new Class[] { mxbeanInterface,
                NotificationEmitter.class };
    } else {
        interfaces = new Class[] { mxbeanInterface };
    }

    result = (T) Proxy.newProxyInstance(interfaces[0].getClassLoader(),
            interfaces, new OpenTypeMappingIHandler(connection,
                    mxbeanInterface.getName(), mxbeanName));
    return result;
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
public static void addWatchDogToAllPools(final long threshold,
    final NotificationListener listener) {
  final MemoryMXBean memBean = ManagementFactory.getMemoryMXBean();
  final NotificationEmitter ne = (NotificationEmitter) memBean;

  ne.addNotificationListener(listener, null, null);

  final List<MemoryPoolMXBean> memPools = ManagementFactory
      .getMemoryPoolMXBeans();
  for (final MemoryPoolMXBean mp : memPools) {
    if (mp.isUsageThresholdSupported()) {
      final MemoryUsage mu = mp.getUsage();
      final long max = mu.getMax();
      final long alert = (max * threshold) / 100;
      // LOG.info("Setting a threshold shutdown on pool: " + mp.getName()
      // + " for: " + alert);
      mp.setUsageThreshold(alert);

    }
  }
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
void install() {
  Preconditions.checkState(!installed, "RetainedHeapLimiter installed twice");
  installed = true;
  List<GarbageCollectorMXBean> gcbeans = ManagementFactory.getGarbageCollectorMXBeans();
  boolean foundTenured = false;
  // Examine all collectors and register for notifications from those which collect the tenured
  // space. Normally there is one such collector.
  for (GarbageCollectorMXBean gcbean : gcbeans) {
    boolean collectsTenured = false;
    for (String name : gcbean.getMemoryPoolNames()) {
      collectsTenured |= isTenuredSpace(name);
    }
    if (collectsTenured) {
      foundTenured = true;
      NotificationEmitter emitter = (NotificationEmitter) gcbean;
      emitter.addNotificationListener(this, null, null);
    }
  }
  if (!foundTenured) {
    throw new IllegalStateException(
        "Can't find tenured space; update this class for a new collector");
  }
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
/**
 * Default constructor.
 * 
 * @param memoryThresholdFactor amount of memory to be considered 'enough memory'.
 * @throws IllegalArgumentException If memoryThresholdFactor is not strictly between 0.0 and 1.0.
 */
public LowMemoryDetector(final double memoryThresholdFactor) {
	checkArgument(memoryThresholdFactor > 0.0 && memoryThresholdFactor < 1.0,
			"Expected memoryThresholdFactor to be between 0.0 and 1.0, %s is not.", memoryThresholdFactor);

	isLowMemory = false;

	// Find the tenured heap
	tenuredHeap = findTenuredHeap();
	checkNotNull(tenuredHeap, "Expected tenuredHeap to be not null.");
	tenuredHeapSize = tenuredHeap.getUsage().getMax();
	log.debug("Determined the tenured heap as '{}' (size: {} B).", tenuredHeap.getName(), tenuredHeapSize);

	// Monitor tenured heap
	memoryThreshold = (long) (tenuredHeapSize * memoryThresholdFactor);
	tenuredHeap.setCollectionUsageThreshold(memoryThreshold);
	log.debug("Low memory threshold is {} B.", memoryThreshold);

	// Add notification listener
	final NotificationEmitter notificationEmitter = (NotificationEmitter) ManagementFactory.getMemoryMXBean();
	notificationEmitter.addNotificationListener(this, null, null);
}
 

import javax.management.NotificationEmitter; //导入依赖的package包/类
private static void subscribeForGc() {
        ManagementFactory.getGarbageCollectorMXBeans().stream().filter(bean -> bean instanceof NotificationEmitter).forEach(bean -> {
            ((NotificationEmitter) bean).addNotificationListener((notification, handback) -> {
//                System.err.println("Notified");
                if (GARBAGE_COLLECTION_NOTIFICATION.equals(notification.getType())) {
                    GarbageCollectionNotificationInfo info = from((CompositeData) notification.getUserData());
                    com.sun.management.GarbageCollectorMXBean mxBean = (com.sun.management.GarbageCollectorMXBean) handback;

//                    System.err.println("GC notification");

                    GcInfo gcInfo = info.getGcInfo();
                    if (gcInfo != null) {

                        System.out.println(info.getGcName() + ", " + info.getGcAction() + ", " + mxBean.getName() + ", " + info.getGcCause() + ", " + gcInfo.getMemoryUsageBeforeGc() + ", " + gcInfo.getMemoryUsageAfterGc());
                    }
                }
            }, null, bean);
        });
    }