| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package org.netbeans.editor; |
| |
| import java.beans.PropertyChangeListener; |
| import java.beans.PropertyChangeEvent; |
| import java.lang.ref.WeakReference; |
| import java.util.ArrayList; |
| |
| /** |
| * Similair functionality as PropertyChangeSupport but holds only |
| * weak references to listener classes |
| * |
| * @author Miloslav Metelka |
| * @version 1.00 |
| */ |
| |
| public class WeakPropertyChangeSupport { |
| |
| private transient ArrayList listeners = new ArrayList(); |
| |
| private transient ArrayList interestNames = new ArrayList(); |
| |
| |
| /** Add weak listener to listen to change of any property. The caller must |
| * hold the listener object in some instance variable to prevent it |
| * from being garbage collected. |
| */ |
| public synchronized void addPropertyChangeListener(PropertyChangeListener l) { |
| addLImpl(null, l); |
| } |
| |
| /** Add weak listener to listen to change of the specified property. |
| * The caller must hold the listener object in some instance variable |
| * to prevent it from being garbage collected. |
| */ |
| public synchronized void addPropertyChangeListener(String propertyName, |
| PropertyChangeListener l) { |
| addLImpl(propertyName, l); |
| } |
| |
| /** Remove listener for changes in properties */ |
| public synchronized void removePropertyChangeListener(PropertyChangeListener l) { |
| int cnt = listeners.size(); |
| for (int i = 0; i < cnt; i++) { |
| Object o = ((WeakReference)listeners.get(i)).get(); |
| if (o == null || o == l) { // remove null references and the required one |
| listeners.remove(i); |
| interestNames.remove(i); |
| i--; |
| cnt--; |
| } |
| } |
| } |
| |
| public void firePropertyChange(Object source, String propertyName, |
| Object oldValue, Object newValue) { |
| if (oldValue != null && newValue != null && oldValue.equals(newValue)) { |
| return; |
| } |
| PropertyChangeListener la[]; |
| String isa[]; |
| int cnt; |
| synchronized (this) { |
| cnt = listeners.size(); |
| la = new PropertyChangeListener[cnt]; |
| for (int i = 0; i < cnt; i++) { |
| PropertyChangeListener l = (PropertyChangeListener) |
| ((WeakReference)listeners.get(i)).get(); |
| if (l == null) { // remove null references |
| listeners.remove(i); |
| interestNames.remove(i); |
| i--; |
| cnt--; |
| } else { |
| la[i] = l; |
| } |
| } |
| isa = (String [])interestNames.toArray(new String[cnt]); |
| } |
| |
| // now create and fire the event |
| PropertyChangeEvent evt = new PropertyChangeEvent(source, propertyName, |
| oldValue, newValue); |
| for (int i = 0; i < cnt; i++) { |
| if (isa[i] == null || propertyName == null || isa[i].equals(propertyName)) { |
| la[i].propertyChange(evt); |
| } |
| } |
| } |
| |
| private void addLImpl(String sn, PropertyChangeListener l) { |
| listeners.add(new WeakReference(l)); |
| interestNames.add(sn); |
| } |
| |
| } |