org.modeshape.graph.observe
Class ChangeObservers

java.lang.Object
  org.modeshape.graph.observe.ChangeObservers

All Implemented Interfaces:

Observable

@ThreadSafe
public class ChangeObservers
extends Object
implements Observable

Reusable manager of change listeners, typically employed by another Observable implementation.

Nested Class Summary

protected class

ChangeObservers.ObserverReference A WeakReference implementation that provides a valid

Constructor Summary

ChangeObservers()

Method Summary

void	broadcast(Changes changes) Broadcast the supplied changes to the registered observers.
boolean	isEmpty() Determine whether there are any observers at the time this method is called.
boolean	register(Observer observer) Register the supplied observer.
void	shutdown() Unregister all registered observers, and mark this as no longer accepting new registered observers.
boolean	unregister(Observer observer) Unregister the supplied observer.

Methods inherited from class java.lang.Object

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

Constructor Detail

ChangeObservers

public ChangeObservers()

Method Detail

register

public boolean register(Observer observer)

Register the supplied observer. This method does nothing if the observer reference is null.

Specified by:

register in interface Observable

Parameters:

observer - the observer to be added; may be null

Returns:

true if the observer was added, or false if the observer was null, if the observer was already registered, or if the observer could not be added

See Also:

Observable.register(org.modeshape.graph.observe.Observer)

unregister

public boolean unregister(Observer observer)

Unregister the supplied observer. This method does nothing if the observer reference is null.

Specified by:

unregister in interface Observable

Parameters:

observer - the observer to be removed; may not be null

Returns:

true if the observer was removed, or false if the observer was null or if the observer was not registered on this source

See Also:

Observable.unregister(org.modeshape.graph.observe.Observer)

shutdown

public void shutdown()

Unregister all registered observers, and mark this as no longer accepting new registered observers.

isEmpty

public boolean isEmpty()

Determine whether there are any observers at the time this method is called.

Returns:

true if there are currently no observers, or false if there is at least one observer

broadcast

public void broadcast(Changes changes)

Broadcast the supplied changes to the registered observers.

Parameters:

changes - the changes to broadcast

Throws:

IllegalArgumentException - if the changes reference is null