com.sharkysoft.fig.extra.util

Class ListenerRegistry<Listener>

java.lang.Object

com.sharkysoft.fig.extra.util.ListenerRegistry<Listener>

public class ListenerRegistry<Listener>
extends Object

Manages event listener subscriptions.

Details: A ListenerRegistry maintains a list of subscribed listeners that have expressed their interest in notifications for certain types of events. ListenerRegistry is designed to support classes that accept listener subscriptions, such as AWT and Swing components.

ListenerRegistry is completely thread-safe. The client code does not need to be concerned about concurrent accesses to the subscriber list.

Since:

1999.08.13

Author:

Sharky

Constructor Summary

Constructors

Constructor and Description
ListenerRegistry()

Method Summary

Methods

Modifier and Type	Method and Description
Iterator<Listener>	iterateListeners() Iterates registered listeners.
void	registerListener(Listener iListener) Registers a listener.
void	unregisterListener(Listener iListener) Unregisters a listener.

Methods inherited from class java.lang.Object

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

Constructor Detail

ListenerRegistry

public ListenerRegistry()

Method Detail

registerListener

public void registerListener(Listener iListener)

Registers a listener.

Details: registerListener registers the given listener to receive notifications from the owner of this registry. A listener cannot be added twice. No action is taken if the listener is already registered.

Parameters:

iListener - the listener to register

unregisterListener

public void unregisterListener(Listener iListener)

Unregisters a listener.

Details: unregisterListener unregisters the given listener so that it no longer receives messages from the registry owner. No action is taken if the listener is not registered.

Listeners should unregister themselves when they no longer need to receive messages.

Parameters:

iListener - the listener to unregister

iterateListeners

public Iterator<Listener> iterateListeners()

Iterates registered listeners.

Details: iterateListeners returns an Iterator that walks through the list of all listeners that were registered at the moment this method was invoked. (The Iterator is based on a "snapshot" of this registry.) Since the returned Iterator exists independently from the internally stored listener list, elements may be added or removed from this registery while the iterator is still in use.

Returns:

the snapshot Iterator