/*******************************************************************************
* Copyright (c) 2006, 2007 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.core.databinding.observable;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.ListenerList;
/**
* Listener management implementation. Exposed to subclasses in form of
* {@link AbstractObservable} and {@link ChangeSupport}.
*
* @since 1.0
*
*/
/* package */ class ChangeManager {
ListenerList[] listenerLists = null;
Object listenerTypes[] = null;
private Realm realm;
/**
* @param realm
*
*/
/* package */ ChangeManager(Realm realm) {
Assert.isNotNull(realm);
this.realm = realm;
}
/**
* @param listenerType
* @param listener
*/
protected void addListener(Object listenerType,
IObservablesListener listener) {
int listenerTypeIndex = findListenerTypeIndex(listenerType);
if (listenerTypeIndex == -1) {
int length;
if (listenerTypes == null) {
length = 0;
listenerTypes = new Object[1];
listenerLists = new ListenerList[1];
} else {
length = listenerTypes.length;
System.arraycopy(listenerTypes, 0,
listenerTypes = new Object[length + 1], 0, length);
System
.arraycopy(listenerLists, 0,
listenerLists = new ListenerList[length + 1],
0, length);
}
listenerTypes[length] = listenerType;
listenerLists[length] = new ListenerList();
boolean hadListeners = hasListeners();
listenerLists[length].add(listener);
if (!hadListeners) {
this.firstListenerAdded();
}
return;
}
ListenerList listenerList = listenerLists[listenerTypeIndex];
boolean hadListeners = true;
if (listenerList.size() == 0) {
hadListeners = hasListeners();
}
listenerList.add(listener);
if (!hadListeners) {
firstListenerAdded();
}
}
/**
* @param listenerType
* @param listener
*/
protected void removeListener(Object listenerType,
IObservablesListener listener) {
int listenerTypeIndex = findListenerTypeIndex(listenerType);
if (listenerTypeIndex != -1) {
listenerLists[listenerTypeIndex].remove(listener);
if (listenerLists[listenerTypeIndex].size() == 0) {
if (!hasListeners()) {
this.lastListenerRemoved();
}
}
}
}
protected boolean hasListeners() {
if (listenerTypes == null) {
return false;
}
for (int i = 0; i < listenerTypes.length; i++) {
if (listenerLists[i].size() > 0) {
return true;
}
}
return false;
}
private int findListenerTypeIndex(Object listenerType) {
if (listenerTypes != null) {
for (int i = 0; i < listenerTypes.length; i++) {
if (listenerTypes[i] == listenerType) {
return i;
}
}
}
return -1;
}
protected void fireEvent(ObservableEvent event) {
Object listenerType = event.getListenerType();
int listenerTypeIndex = findListenerTypeIndex(listenerType);
if (listenerTypeIndex != -1) {
Object[] listeners = listenerLists[listenerTypeIndex]
.getListeners();
for (int i = 0; i < listeners.length; i++) {
event.dispatch((IObservablesListener) listeners[i]);
}
}
}
/**
*
*/
protected void firstListenerAdded() {
}
/**
*
*/
protected void lastListenerRemoved() {
}
/**
*
*/
public void dispose() {
listenerLists = null;
listenerTypes = null;
realm = null;
}
/**
* @return Returns the realm.
*/
public Realm getRealm() {
return realm;
}
}