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/*******************************************************************************
* Copyright (c) 2008 Matthew Hall and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Matthew Hall - initial API and implementation (bug 237718)
* Matthew Hall - but 246626
******************************************************************************/
package org.eclipse.core.databinding.observable;
import org.eclipse.core.internal.databinding.Util;
/**
* An observable which decorates another observable
*
* @since 1.2
*
*/
public class DecoratingObservable extends AbstractObservable implements
IDecoratingObservable {
private IObservable decorated;
private IStaleListener staleListener;
private boolean disposedDecoratedOnDispose;
/**
* Constructs a DecoratingObservable which decorates the given observable.
*
* @param decorated
* the observable being decorated.
* @param disposeDecoratedOnDispose
* whether the decorated observable should be disposed when the
* decorator is disposed
*/
public DecoratingObservable(IObservable decorated,
boolean disposeDecoratedOnDispose) {
super(decorated.getRealm());
this.decorated = decorated;
this.disposedDecoratedOnDispose = disposeDecoratedOnDispose;
}
public IObservable getDecorated() {
return decorated;
}
public boolean isStale() {
getterCalled();
return decorated.isStale();
}
protected void getterCalled() {
ObservableTracker.getterCalled(this);
}
protected void firstListenerAdded() {
if (staleListener == null) {
staleListener = new IStaleListener() {
public void handleStale(StaleEvent staleEvent) {
DecoratingObservable.this.handleStaleEvent(staleEvent);
}
};
}
decorated.addStaleListener(staleListener);
}
protected void lastListenerRemoved() {
if (staleListener != null) {
decorated.removeStaleListener(staleListener);
staleListener = null;
}
}
/**
* Called whenever a StaleEvent is received from the decorated observable.
* By default, this method fires the stale event again, with the decorating
* observable as the event source. Subclasses may override to provide
* different behavior.
*
* @param event
* the stale event received from the decorated observable
*/
protected void handleStaleEvent(StaleEvent event) {
fireStale();
}
public boolean equals(Object obj) {
getterCalled();
if (obj == this)
return true;
if (obj == null)
return false;
if (getClass() == obj.getClass()) {
DecoratingObservable other = (DecoratingObservable) obj;
return Util.equals(this.decorated, other.decorated);
}
return Util.equals(decorated, obj);
}
public int hashCode() {
getterCalled();
return decorated.hashCode();
}
public synchronized void dispose() {
if (decorated != null && staleListener != null) {
decorated.removeStaleListener(staleListener);
}
if (decorated != null) {
if (disposedDecoratedOnDispose)
decorated.dispose();
decorated = null;
}
staleListener = null;
super.dispose();
}
}
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