/*******************************************************************************
* Copyright (c) 2004, 2010 IBM Corporation 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jface.resource;
import java.util.Set;
import org.eclipse.core.commands.common.EventManager;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
/**
* Abstract base class for various JFace registries.
*
* @since 3.0
*/
public abstract class ResourceRegistry extends EventManager {
/**
* Adds a property change listener to this registry.
*
* @param listener a property change listener
*/
public void addListener(IPropertyChangeListener listener) {
addListenerObject(listener);
}
/**
* Disposes all currently allocated resources.
*/
protected abstract void clearCaches();
/**
* @return the set of keys this manager knows about. This collection
* should be immutable.
*/
public abstract Set getKeySet();
/**
* Return whether or not the receiver has a value for the supplied key.
*
* @param key the key
* @return <code>true</code> if there is a value for this key
*/
public abstract boolean hasValueFor(String key);
/**
* Fires a <code>PropertyChangeEvent</code>.
*
* @param name the name of the symbolic value that is changing.
* @param oldValue the old value.
* @param newValue the new value.
*/
protected void fireMappingChanged(String name, Object oldValue,
Object newValue) {
final Object[] myListeners = getListeners();
if (myListeners.length > 0) {
PropertyChangeEvent event = new PropertyChangeEvent(this, name,
oldValue, newValue);
for (int i = 0; i < myListeners.length; ++i) {
try {
((IPropertyChangeListener) myListeners[i])
.propertyChange(event);
} catch (Exception e) {
// TODO: how to log?
}
}
}
}
/**
* Removes the given listener from this registry. Has no effect if the
* listener is not registered.
*
* @param listener a property change listener
*/
public void removeListener(IPropertyChangeListener listener) {
removeListenerObject(listener);
}
}