org.jboss.dashboard.commons.events
Class Publisher

java.lang.Object
  org.jboss.dashboard.commons.events.Publisher

public class Publisher
extends Object

The publisher party int the publish/subscribe GoF design pattern.

WARNING: In order to solve the -lapsed listener- problem the reference to the subscriber stored by the Publisher is weak. This it means that if the Subscriber reference is lost then is also automatically removed from the subscribers list. To avoid this issue ensure that your Subscriber instance is referenced in your object model and exists as long as the Publisher is alive.

Field Summary

static int	EVENT_ALL The event representing all events.
protected Map	subscribers The registered subscribers grouped by eventId.

Constructor Summary

Publisher()

Method Summary

Map	getSubscribers() Retrieve registered subscribers.
List	getSubscribers(int eventId) Retrieve registered Subscribers for a specified event.
void	notifyEvent(int eventId, Object eventInfo) Interface used to fire events.
void	subscribe(Collection c, int eventId) Subscribe a collection subscribers for a concrete event.
void	subscribe(Subscriber subscriber) Register a subscriber interested in ALL events.
void	subscribe(Subscriber subscriber, int eventId) Register a subscriber interested in a single event.
void	unsubscribe(Subscriber subscriber) Removes a registered subscriber.
void	unsubscribe(Subscriber subscriber, int eventId) Removes a registered subscriber.

Methods inherited from class java.lang.Object

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

Field Detail

EVENT_ALL

public static final int EVENT_ALL

The event representing all events.

NOTE: EVENT_ALL=0 is a reserved identifier.

See Also:

Constant Field Values

subscribers

protected Map subscribers

The registered subscribers grouped by eventId.

Constructor Detail

Publisher

public Publisher()

Method Detail

subscribe

public void subscribe(Subscriber subscriber)

Register a subscriber interested in ALL events.

subscribe

public void subscribe(Subscriber subscriber,
                      int eventId)

Register a subscriber interested in a single event.

Parameters:

eventId - The event interested in.

NOTE: EVENT_ALL=0 is a reserved identifier.

subscribe

public void subscribe(Collection c,
                      int eventId)

Subscribe a collection subscribers for a concrete event.

unsubscribe

public void unsubscribe(Subscriber subscriber)

Removes a registered subscriber.

unsubscribe

public void unsubscribe(Subscriber subscriber,
                        int eventId)

Removes a registered subscriber.

Parameters:

eventId - The event interested in.

getSubscribers

public Map getSubscribers()

Retrieve registered subscribers.

Returns:

A map of eventId (Integer) / Subscriber (List). If no subscribers are registered for an event then no entry is returned.

getSubscribers

public List getSubscribers(int eventId)

Retrieve registered Subscribers for a specified event.

notifyEvent

public void notifyEvent(int eventId,
                        Object eventInfo)

Interface used to fire events.

Parameters:

eventInfo - The object where event occurs.