FileDocCategorySizeDatePackage
NotificationBroadcasterSupport.javaAPI DocJava SE 6 API12198Tue Jun 10 00:26:14 BST 2008javax.management

NotificationBroadcasterSupport

public class NotificationBroadcasterSupport extends Object implements NotificationEmitter

Provides an implementation of {@link javax.management.NotificationEmitter NotificationEmitter} interface. This can be used as the super class of an MBean that sends notifications.

By default, the notification dispatch model is synchronous. That is, when a thread calls sendNotification, the NotificationListener.handleNotification method of each listener is called within that thread. You can override this default by overriding handleNotification in a subclass, or by passing an Executor to the constructor.

If the method call of a filter or listener throws an {@link Exception}, then that exception does not prevent other listeners from being invoked. However, if the method call of a filter or of {@code Executor.execute} or of {@code handleNotification} (when no {@code Excecutor} is specified) throws an {@link Error}, then that {@code Error} is propagated to the caller of {@link #sendNotification sendNotification}.

Remote listeners added using the JMX Remote API (see JMXConnector) are not usually called synchronously. That is, when sendNotification returns, it is not guaranteed that any remote listeners have yet received the notification.

since
1.5

Fields Summary
private List
listenerList
private final Executor
executor
private final MBeanNotificationInfo[]
notifInfo
private static final Executor
defaultExecutor
private static final MBeanNotificationInfo[]
NO_NOTIFICATION_INFO
private static final ClassLogger
logger
Constructors Summary
public NotificationBroadcasterSupport()
Constructs a NotificationBroadcasterSupport where each listener is invoked by the thread sending the notification. This constructor is equivalent to {@link NotificationBroadcasterSupport#NotificationBroadcasterSupport(Executor, MBeanNotificationInfo[] info) NotificationBroadcasterSupport(null, null)}.

	this(null, (MBeanNotificationInfo[]) null);
public NotificationBroadcasterSupport(Executor executor)
Constructs a NotificationBroadcasterSupport where each listener is invoked using the given {@link java.util.concurrent.Executor}. When {@link #sendNotification sendNotification} is called, a listener is selected if it was added with a null {@link NotificationFilter}, or if {@link NotificationFilter#isNotificationEnabled isNotificationEnabled} returns true for the notification being sent. The call to NotificationFilter.isNotificationEnabled takes place in the thread that called sendNotification. Then, for each selected listener, {@link Executor#execute executor.execute} is called with a command that calls the handleNotification method. This constructor is equivalent to {@link NotificationBroadcasterSupport#NotificationBroadcasterSupport(Executor, MBeanNotificationInfo[] info) NotificationBroadcasterSupport(executor, null)}.

param
executor an executor used by the method sendNotification to send each notification. If it is null, the thread calling sendNotification will invoke the handleNotification method itself.
since
1.6

	this(executor, (MBeanNotificationInfo[]) null);
public NotificationBroadcasterSupport(MBeanNotificationInfo info)

Constructs a NotificationBroadcasterSupport with information about the notifications that may be sent. Each listener is invoked by the thread sending the notification. This constructor is equivalent to {@link NotificationBroadcasterSupport#NotificationBroadcasterSupport(Executor, MBeanNotificationInfo[] info) NotificationBroadcasterSupport(null, info)}.

If the info array is not empty, then it is cloned by the constructor as if by {@code info.clone()}, and each call to {@link #getNotificationInfo()} returns a new clone.

param
info an array indicating, for each notification this MBean may send, the name of the Java class of the notification and the notification type. Can be null, which is equivalent to an empty array.
since
1.6

	this(null, info);
public NotificationBroadcasterSupport(Executor executor, MBeanNotificationInfo info)

Constructs a NotificationBroadcasterSupport with information about the notifications that may be sent, and where each listener is invoked using the given {@link java.util.concurrent.Executor}.

When {@link #sendNotification sendNotification} is called, a listener is selected if it was added with a null {@link NotificationFilter}, or if {@link NotificationFilter#isNotificationEnabled isNotificationEnabled} returns true for the notification being sent. The call to NotificationFilter.isNotificationEnabled takes place in the thread that called sendNotification. Then, for each selected listener, {@link Executor#execute executor.execute} is called with a command that calls the handleNotification method.

If the info array is not empty, then it is cloned by the constructor as if by {@code info.clone()}, and each call to {@link #getNotificationInfo()} returns a new clone.

param
executor an executor used by the method sendNotification to send each notification. If it is null, the thread calling sendNotification will invoke the handleNotification method itself.
param
info an array indicating, for each notification this MBean may send, the name of the Java class of the notification and the notification type. Can be null, which is equivalent to an empty array.
since
1.6

	this.executor = (executor != null) ? executor : defaultExecutor;

	notifInfo = info == null ? NO_NOTIFICATION_INFO : info.clone();
Methods Summary
public voidaddNotificationListener(javax.management.NotificationListener listener, javax.management.NotificationFilter filter, java.lang.Object handback)
Adds a listener.

param
listener The listener to receive notifications.
param
filter The filter object. If filter is null, no filtering will be performed before handling notifications.
param
handback An opaque object to be sent back to the listener when a notification is emitted. This object cannot be used by the Notification broadcaster object. It should be resent unchanged with the notification to the listener.
exception
IllegalArgumentException thrown if the listener is null.
see
#removeNotificationListener


        if (listener == null) {
            throw new IllegalArgumentException ("Listener can't be null") ;
        }

	listenerList.add(new ListenerInfo(listener, filter, handback));
public javax.management.MBeanNotificationInfo[]getNotificationInfo()

	if (notifInfo.length == 0)
	    return notifInfo;
	else
	    return notifInfo.clone();
protected voidhandleNotification(javax.management.NotificationListener listener, javax.management.Notification notif, java.lang.Object handback)

This method is called by {@link #sendNotification sendNotification} for each listener in order to send the notification to that listener. It can be overridden in subclasses to change the behavior of notification delivery, for instance to deliver the notification in a separate thread.

The default implementation of this method is equivalent to 

listener.handleNotification(notif, handback);

param
listener the listener to which the notification is being delivered.
param
notif the notification being delivered to the listener.
param
handback the handback object that was supplied when the listener was added.
since.unbundled
JMX 1.2

	listener.handleNotification(notif, handback);
public voidremoveNotificationListener(javax.management.NotificationListener listener)


	ListenerInfo wildcard = new WildcardListenerInfo(listener);
	boolean removed =
	    listenerList.removeAll(Collections.singleton(wildcard));
	if (!removed)
	    throw new ListenerNotFoundException("Listener not registered");
public voidremoveNotificationListener(javax.management.NotificationListener listener, javax.management.NotificationFilter filter, java.lang.Object handback)


	ListenerInfo li = new ListenerInfo(listener, filter, handback);
	boolean removed = listenerList.remove(li);
	if (!removed) {
	    throw new ListenerNotFoundException("Listener not registered " +
						"(with this filter and " +
						"handback)");
	    // or perhaps not registered at all
	}
public voidsendNotification(javax.management.Notification notification)
Sends a notification. If an {@code Executor} was specified in the constructor, it will be given one task per selected listener to deliver the notification to that listener.

param
notification The notification to send.


	if (notification == null) {
	    return;
	}
        
	boolean enabled;

	for (ListenerInfo li : listenerList) {
	    try {
		enabled = li.filter == null ||
		    li.filter.isNotificationEnabled(notification);
	    } catch (Exception e) {
		if (logger.debugOn()) {
		    logger.debug("sendNotification", e);
		}

		continue;
	    }

	    if (enabled) {
		executor.execute(new SendNotifJob(notification, li));
	    }
	}