org.apache.commons.events.observable
Class ObservableSet

java.lang.Object
  org.apache.commons.collections.collection.AbstractCollectionDecorator
      org.apache.commons.events.observable.ObservableCollection
          org.apache.commons.events.observable.ObservableSet

All Implemented Interfaces:

Iterable, Collection, Set

Direct Known Subclasses:

ObservableSortedSet

public class ObservableSet
extends ObservableCollection
implements Set

Decorates a Set implementation to observe modifications.

Each modifying method call made on this Set is forwarded to a ModificationHandler. The handler manages the event, notifying listeners and optionally vetoing changes. The default handler is StandardModificationHandler. See this class for details of configuration available.

Since:

Commons Events 1.0

Version:

$Revision: 155443 $ $Date: 2005-02-26 13:19:51 +0000 (Sat, 26 Feb 2005) $

Author:

Stephen Colebourne

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.commons.events.observable.ObservableCollection

ObservableCollection.ObservableIterator

Field Summary

Fields inherited from class org.apache.commons.events.observable.ObservableCollection

handler

Fields inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator

collection

Constructor Summary

protected

ObservableSet(Set set, Object listener) Constructor that wraps (not copies) and takes a handler.

Method Summary

static ObservableSet	decorate(Set set) Factory method to create an observable set.
static ObservableSet	decorate(Set set, Object listener) Factory method to create an observable set using a listener or a handler.

Methods inherited from class org.apache.commons.events.observable.ObservableCollection

add, addAll, clear, createHandler, decorate, decorate, getHandler, iterator, registerFactory, remove, removeAll, retainAll

Methods inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator

contains, containsAll, equals, getCollection, hashCode, isEmpty, size, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set

add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray

Constructor Detail

ObservableSet

protected ObservableSet(Set set,
                        Object listener)

Constructor that wraps (not copies) and takes a handler.

The handler implementation is determined by the listener parameter via the registered factories. The listener may be a manually configured ModificationHandler instance.

Parameters:

set - the set to decorate, must not be null

listener - the listener, may be null

Throws:

IllegalArgumentException - if the set is null

Method Detail

decorate

public static ObservableSet decorate(Set set)

Factory method to create an observable set.

A StandardModificationHandler will be created. This can be accessed by ObservableCollection.getHandler() to add listeners.

Parameters:

set - the set to decorate, must not be null

Returns:

the observed Set

Throws:

IllegalArgumentException - if the collection is null

decorate

public static ObservableSet decorate(Set set,
                                     Object listener)

Factory method to create an observable set using a listener or a handler.

A lot of functionality is available through this method. If you don't need the extra functionality, simply implement the StandardModificationListener interface and pass it in as the second parameter.

Internally, an ObservableSet relies on a ModificationHandler. The handler receives all the events and processes them, typically by calling listeners. Different handler implementations can be plugged in to provide a flexible event system.

The handler implementation is determined by the listener parameter via the registered factories. The listener may be a manually configured ModificationHandler instance.

The listener is defined as an Object for maximum flexibility. It does not have to be a listener in the classic JavaBean sense. It is entirely up to the factory and handler as to how the parameter is interpretted. An IllegalArgumentException is thrown if no suitable handler can be found for this listener.

A null listener will create a StandardModificationHandler.

Parameters:

set - the set to decorate, must not be null

listener - set listener, may be null

Returns:

the observed set

Throws:

IllegalArgumentException - if the set is null

IllegalArgumentException - if there is no valid handler for the listener