net.eduvax.util

Class ObserverManager<T>

java.lang.Object

net.eduvax.util.ObserverManager<T>

public class ObserverManager<T>
extends java.lang.Object

Observable's observers registration and notification manager. Each Observable must have its own ObserverManager to delagate all its observers management. The observer manager is published by implementing accessor from Observable interface to let any observer register or deregister itself. Then an observable must invoke Notify(this) to its ObserverManager that will relay the call to all registered observers.

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Vector<Observer<T>>	_observers Registered observers list.

Constructor Summary

Constructors

Constructor and Description
ObserverManager()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(Observer<T> obs) Register an observer.
void	notify(T sender) Notifiy observers.
boolean	remove(Observer<T> obs) Deregister an observer.

Methods inherited from class java.lang.Object

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

Field Detail

_observers

private java.util.Vector<Observer<T>> _observers

Registered observers list.

Constructor Detail

ObserverManager

public ObserverManager()

Method Detail

add

public boolean add(Observer<T> obs)

Register an observer.

Parameters:

obs - observer to register.

Returns:

- true: observer is successfully registered. - false: observer not registered (for example if already registered)

remove

public boolean remove(Observer<T> obs)

Deregister an observer.

Parameters:

obs - observer to remove

Returns:

- true: observer removed. - false: observer not removed (for exemple because not present)

notify

public void notify(T sender)

Notifiy observers.

Cette méthode ne devrait être appelé que par l'observable dont ce gestionnaire est membre avec pour paramètre l'observable lui-même.

warning: This method is synchronized on the registered observer list. So observers ObservableChanged() method should notbe too long to avoid risk of hanging registration from other thread. ObservableChanged() implementation should also not invoke ObserverManager's add() and remove() methods.

Parameters:

sender - notification source.