Class NotificationBroadcasterSupport

All Implemented Interfaces:
NotificationBroadcaster, NotificationEmitter
Direct Known Subclasses:
JMXConnectorServer, Monitor, RelationService, Timer 
public class NotificationBroadcasterSupport
extends Object
implements NotificationEmitter

Provides an implementation of 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 Exception, then that exception does not prevent other listeners from being invoked. However, if the method call of a filter or of Executor.execute or of handleNotification (when no Excecutor is specified) throws an Error, then that Error is propagated to the caller of 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

Constructor Summary

Constructors
Constructor Description
NotificationBroadcasterSupport()

Constructs a NotificationBroadcasterSupport where each listener is invoked by the thread sending the notification.
NotificationBroadcasterSupport​(Executor executor)

Constructs a NotificationBroadcasterSupport where each listener is invoked using the given Executor.
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 Executor.
NotificationBroadcasterSupport​(MBeanNotificationInfo... info)

Constructs a NotificationBroadcasterSupport with information about the notifications that may be sent.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type Method Description
void addNotificationListener​(NotificationListener listener, NotificationFilter filter, Object handback)

Adds a listener.
protected void handleNotification​(NotificationListener listener, Notification notif, Object handback)

This method is called by sendNotification for each listener in order to send the notification to that listener.
void sendNotification​(Notification notification)

Sends a notification.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods declared in interface javax.management.NotificationBroadcaster

getNotificationInfo, removeNotificationListener

Methods declared in interface javax.management.NotificationEmitter

removeNotificationListener

Constructor Detail

NotificationBroadcasterSupport

public NotificationBroadcasterSupport()

Constructs a NotificationBroadcasterSupport where each listener is invoked by the thread sending the notification. This constructor is equivalent to NotificationBroadcasterSupport(null, null).

NotificationBroadcasterSupport

public NotificationBroadcasterSupport​(Executor executor)

Constructs a NotificationBroadcasterSupport where each listener is invoked using the given Executor. When sendNotification is called, a listener is selected if it was added with a null NotificationFilter, or if 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, executor.execute is called with a command that calls the handleNotification method. This constructor is equivalent to NotificationBroadcasterSupport(executor, null).

Parameters:
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

NotificationBroadcasterSupport

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 NotificationBroadcasterSupport(null, info).

If the info array is not empty, then it is cloned by the constructor as if by info.clone(), and each call to NotificationBroadcaster.getNotificationInfo() returns a new clone.

Parameters:
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

NotificationBroadcasterSupport

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 Executor.

When sendNotification is called, a listener is selected if it was added with a null NotificationFilter, or if 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, 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 info.clone(), and each call to NotificationBroadcaster.getNotificationInfo() returns a new clone.

Parameters:
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.
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

Method Detail

addNotificationListener

public void addNotificationListener​(NotificationListener listener,
                                    NotificationFilter filter,
                                    Object handback)

Adds a listener.

Specified by:
addNotificationListener in interface NotificationBroadcaster
Parameters:
listener - The listener to receive notifications.
filter - The filter object. If filter is null, no filtering will be performed before handling notifications.
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.
Throws:
IllegalArgumentException - thrown if the listener is null.
See Also:
NotificationBroadcaster.removeNotificationListener(javax.management.NotificationListener)

sendNotification

public void sendNotification​(Notification notification)

Sends a notification. If an Executor was specified in the constructor, it will be given one task per selected listener to deliver the notification to that listener.

Parameters:
notification - The notification to send.

handleNotification

protected void handleNotification​(NotificationListener listener,
                                  Notification notif,
                                  Object handback)

This method is called by 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);
Parameters:
listener - the listener to which the notification is being delivered.
notif - the notification being delivered to the listener.
handback - the handback object that was supplied when the listener was added.