NotificationBroadcaster
| javax.management.NotificationBroadcaster |
Class Overview
Interface implemented by an MBean that emits Notifications. It allows a listener to be registered with the MBean as a notification listener.
Notification dispatch
When an MBean emits a notification, it considers each listener that has been
added with addNotificationListener and not
subsequently removed with removeNotificationListener.
If a filter was provided with that listener, and if the filter's
isNotificationEnabled method returns
false, the listener is ignored. Otherwise, the listener's
handleNotification method is called with
the notification, as well as the handback object that was provided to
addNotificationListener.
If the same listener is added more than once, it is considered as many times as it was added. It is often useful to add the same listener with different filters or handback objects.
Implementations of this interface can differ regarding the thread in which the methods of filters and listeners are called.
If the method call of a filter or listener throws an Exception, then that
exception should not prevent other listeners from being invoked. However, if the method
call throws an Error, then it is recommended that processing of the notification
stop at that point, and if it is possible to propagate the Error to the sender of
the notification, this should be done.
New code should use the NotificationEmitter interface
instead.
Implementations of this interface and of NotificationEmitter
should be careful about synchronization. In particular, it is not a good
idea for an implementation to hold any locks while it is calling a
listener. To deal with the possibility that the list of listeners might
change while a notification is being dispatched, a good strategy is to
use a CopyOnWriteArrayList for this list.
Summary
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Adds a listener to this MBean.
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Returns an array indicating, for each notification this MBean may send, the name of the Java class of the notification and the notification type. | |||||||||||
Removes a listener from this MBean.
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Public Methods
public abstract void addNotificationListener (NotificationListener listener, NotificationFilter filter, Object handback)
Adds a listener to this MBean.
Parameters
| listener | The listener object which will handle the notifications emitted by the broadcaster. |
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| 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 | Listener parameter is null. |
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public abstract MBeanNotificationInfo[] getNotificationInfo ()
Returns an array indicating, for each notification this MBean may send, the name of the Java class of the notification and the notification type.
It is not illegal for the MBean to send notifications not described in this array. However, some clients of the MBean server may depend on the array being complete for their correct functioning.
Returns
- the array of possible notifications.
public abstract void removeNotificationListener (NotificationListener listener)
Removes a listener from this MBean. If the listener has been registered with different handback objects or notification filters, all entries corresponding to the listener will be removed.
Parameters
| listener | A listener that was previously added to this MBean. |
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Throws
| ListenerNotFoundException | The listener is not registered with the MBean. |
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