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/*
* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.nashorn.internal.runtime;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* Helper class to manage property listeners and notification.
*/
public class PropertyListenerManager implements PropertyListener {
// These counters are updated in debug mode
private static int listenersAdded;
private static int listenersRemoved;
private static int listenersDead;
/**
* @return the listenersAdded
*/
public static int getListenersAdded() {
return listenersAdded;
}
/**
* @return the listenersRemoved
*/
public static int getListenersRemoved() {
return listenersRemoved;
}
/**
* @return the listenersDead
*/
public static int getListenersDead() {
return listenersDead;
}
/** property listeners for this object. */
private List<WeakReference<PropertyListener>> listeners;
// Property listener management methods
/**
* Add a property listener to this object.
*
* @param listener The property listener that is added.
*/
public final void addPropertyListener(final PropertyListener listener) {
if (listeners == null) {
listeners = new ArrayList<>();
}
if (Context.DEBUG) {
listenersAdded++;
}
listeners.add(new WeakReference<>(listener));
}
/**
* Remove a property listener from this object.
*
* @param listener The property listener that is removed.
*/
public final void removePropertyListener(final PropertyListener listener) {
if (listeners != null) {
final Iterator<WeakReference<PropertyListener>> iter = listeners.iterator();
while (iter.hasNext()) {
if (iter.next().get() == listener) {
if (Context.DEBUG) {
listenersRemoved++;
}
iter.remove();
}
}
}
}
/**
* This method can be called to notify property addition to this object's listeners.
*
* @param object The ScriptObject to which property was added.
* @param prop The property being added.
*/
protected final void notifyPropertyAdded(final ScriptObject object, final Property prop) {
if (listeners != null) {
final Iterator<WeakReference<PropertyListener>> iter = listeners.iterator();
while (iter.hasNext()) {
final WeakReference<PropertyListener> weakRef = iter.next();
final PropertyListener listener = weakRef.get();
if (listener == null) {
if (Context.DEBUG) {
listenersDead++;
}
iter.remove();
} else {
listener.propertyAdded(object, prop);
}
}
}
}
/**
* This method can be called to notify property deletion to this object's listeners.
*
* @param object The ScriptObject from which property was deleted.
* @param prop The property being deleted.
*/
protected final void notifyPropertyDeleted(final ScriptObject object, final Property prop) {
if (listeners != null) {
final Iterator<WeakReference<PropertyListener>> iter = listeners.iterator();
while (iter.hasNext()) {
final WeakReference<PropertyListener> weakRef = iter.next();
final PropertyListener listener = weakRef.get();
if (listener == null) {
if (Context.DEBUG) {
listenersDead++;
}
iter.remove();
} else {
listener.propertyDeleted(object, prop);
}
}
}
}
/**
* This method can be called to notify property modification to this object's listeners.
*
* @param object The ScriptObject to which property was modified.
* @param oldProp The old property being replaced.
* @param newProp The new property that replaces the old property.
*/
protected final void notifyPropertyModified(final ScriptObject object, final Property oldProp, final Property newProp) {
if (listeners != null) {
final Iterator<WeakReference<PropertyListener>> iter = listeners.iterator();
while (iter.hasNext()) {
final WeakReference<PropertyListener> weakRef = iter.next();
final PropertyListener listener = weakRef.get();
if (listener == null) {
if (Context.DEBUG) {
listenersDead++;
}
iter.remove();
} else {
listener.propertyModified(object, oldProp, newProp);
}
}
}
}
// PropertyListener methods
@Override
public final void propertyAdded(final ScriptObject object, final Property prop) {
notifyPropertyAdded(object, prop);
}
@Override
public final void propertyDeleted(final ScriptObject object, final Property prop) {
notifyPropertyDeleted(object, prop);
}
@Override
public final void propertyModified(final ScriptObject object, final Property oldProp, final Property newProp) {
notifyPropertyModified(object, oldProp, newProp);
}
}
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