/*
* @(#)PropertyChangeSupport.java 1.49 04/05/11
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.beans;
import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import sun.awt.EventListenerAggregate;
/**
* This is a utility class that can be used by beans that support bound
* properties. You can use an instance of this class as a member field
* of your bean and delegate various work to it.
*
* This class is serializable. When it is serialized it will save
* (and restore) any listeners that are themselves serializable. Any
* non-serializable listeners will be skipped during serialization.
*
*/
public class PropertyChangeSupport implements java.io.Serializable {
// Manages the listener list.
private transient EventListenerAggregate listeners;
/**
* Constructs a <code>PropertyChangeSupport</code> object.
*
* @param sourceBean The bean to be given as the source for any events.
*/
public PropertyChangeSupport(Object sourceBean) {
if (sourceBean == null) {
throw new NullPointerException();
}
source = sourceBean;
}
/**
* Add a PropertyChangeListener to the listener list.
* The listener is registered for all properties.
* The same listener object may be added more than once, and will be called
* as many times as it is added.
* If <code>listener</code> is null, no exception is thrown and no action
* is taken.
*
* @param listener The PropertyChangeListener to be added
*/
public synchronized void addPropertyChangeListener(
PropertyChangeListener listener) {
if (listener == null) {
return;
}
if (listener instanceof PropertyChangeListenerProxy) {
PropertyChangeListenerProxy proxy =
(PropertyChangeListenerProxy)listener;
// Call two argument add method.
addPropertyChangeListener(proxy.getPropertyName(),
(PropertyChangeListener)proxy.getListener());
} else {
if (listeners == null) {
listeners = new EventListenerAggregate(PropertyChangeListener.class);
}
listeners.add(listener);
}
}
/**
* Remove a PropertyChangeListener from the listener list.
* This removes a PropertyChangeListener that was registered
* for all properties.
* If <code>listener</code> was added more than once to the same event
* source, it will be notified one less time after being removed.
* If <code>listener</code> is null, or was never added, no exception is
* thrown and no action is taken.
*
* @param listener The PropertyChangeListener to be removed
*/
public synchronized void removePropertyChangeListener(
PropertyChangeListener listener) {
if (listener == null) {
return;
}
if (listener instanceof PropertyChangeListenerProxy) {
PropertyChangeListenerProxy proxy =
(PropertyChangeListenerProxy)listener;
// Call two argument remove method.
removePropertyChangeListener(proxy.getPropertyName(),
(PropertyChangeListener)proxy.getListener());
} else {
if (listeners == null) {
return;
}
listeners.remove(listener);
}
}
/**
* Returns an array of all the listeners that were added to the
* PropertyChangeSupport object with addPropertyChangeListener().
* <p>
* If some listeners have been added with a named property, then
* the returned array will be a mixture of PropertyChangeListeners
* and <code>PropertyChangeListenerProxy</code>s. If the calling
* method is interested in distinguishing the listeners then it must
* test each element to see if it's a
* <code>PropertyChangeListenerProxy</code>, perform the cast, and examine
* the parameter.
*
* <pre>
* PropertyChangeListener[] listeners = bean.getPropertyChangeListeners();
* for (int i = 0; i < listeners.length; i++) {
* if (listeners[i] instanceof PropertyChangeListenerProxy) {
* PropertyChangeListenerProxy proxy =
* (PropertyChangeListenerProxy)listeners[i];
* if (proxy.getPropertyName().equals("foo")) {
* // proxy is a PropertyChangeListener which was associated
* // with the property named "foo"
* }
* }
* }
*</pre>
*
* @see PropertyChangeListenerProxy
* @return all of the <code>PropertyChangeListeners</code> added or an
* empty array if no listeners have been added
* @since 1.4
*/
public synchronized PropertyChangeListener[] getPropertyChangeListeners() {
List returnList = new ArrayList();
// Add all the PropertyChangeListeners
if (listeners != null) {
returnList.addAll(Arrays.asList(listeners.getListenersInternal()));
}
// Add all the PropertyChangeListenerProxys
if (children != null) {
Iterator iterator = children.keySet().iterator();
while (iterator.hasNext()) {
String key = (String)iterator.next();
PropertyChangeSupport child =
(PropertyChangeSupport)children.get(key);
PropertyChangeListener[] childListeners =
child.getPropertyChangeListeners();
for (int index = childListeners.length - 1; index >= 0;
index--) {
returnList.add(new PropertyChangeListenerProxy(
key, childListeners[index]));
}
}
}
return (PropertyChangeListener[])(returnList.toArray(
new PropertyChangeListener[0]));
}
/**
* Add a PropertyChangeListener for a specific property. The listener
* will be invoked only when a call on firePropertyChange names that
* specific property.
* The same listener object may be added more than once. For each
* property, the listener will be invoked the number of times it was added
* for that property.
* If <code>propertyName</code> or <code>listener</code> is null, no
* exception is thrown and no action is taken.
*
* @param propertyName The name of the property to listen on.
* @param listener The PropertyChangeListener to be added
*/
public synchronized void addPropertyChangeListener(
String propertyName,
PropertyChangeListener listener) {
if (listener == null || propertyName == null) {
return;
}
if (children == null) {
children = new java.util.Hashtable();
}
PropertyChangeSupport child = (PropertyChangeSupport)children.get(propertyName);
if (child == null) {
child = new PropertyChangeSupport(source);
children.put(propertyName, child);
}
child.addPropertyChangeListener(listener);
}
/**
* Remove a PropertyChangeListener for a specific property.
* If <code>listener</code> was added more than once to the same event
* source for the specified property, it will be notified one less time
* after being removed.
* If <code>propertyName</code> is null, no exception is thrown and no
* action is taken.
* If <code>listener</code> is null, or was never added for the specified
* property, no exception is thrown and no action is taken.
*
* @param propertyName The name of the property that was listened on.
* @param listener The PropertyChangeListener to be removed
*/
public synchronized void removePropertyChangeListener(
String propertyName,
PropertyChangeListener listener) {
if (listener == null || propertyName == null) {
return;
}
if (children == null) {
return;
}
PropertyChangeSupport child = (PropertyChangeSupport)children.get(propertyName);
if (child == null) {
return;
}
child.removePropertyChangeListener(listener);
}
/**
* Returns an array of all the listeners which have been associated
* with the named property.
*
* @param propertyName The name of the property being listened to
* @return all of the <code>PropertyChangeListeners</code> associated with
* the named property. If no such listeners have been added,
* or if <code>propertyName</code> is null, an empty array is
* returned.
*/
public synchronized PropertyChangeListener[] getPropertyChangeListeners(
String propertyName) {
ArrayList returnList = new ArrayList();
if (children != null && propertyName != null) {
PropertyChangeSupport support =
(PropertyChangeSupport)children.get(propertyName);
if (support != null) {
returnList.addAll(
Arrays.asList(support.getPropertyChangeListeners()));
}
}
return (PropertyChangeListener[])(returnList.toArray(
new PropertyChangeListener[0]));
}
/**
* Report a bound property update to any registered listeners.
* No event is fired if old and new are equal and non-null.
*
* @param propertyName The programmatic name of the property
* that was changed.
* @param oldValue The old value of the property.
* @param newValue The new value of the property.
*/
public void firePropertyChange(String propertyName,
Object oldValue, Object newValue) {
if (oldValue != null && newValue != null && oldValue.equals(newValue)) {
return;
}
firePropertyChange(new PropertyChangeEvent(source, propertyName,
oldValue, newValue));
}
/**
* Report an int bound property update to any registered listeners.
* No event is fired if old and new are equal and non-null.
* <p>
* This is merely a convenience wrapper around the more general
* firePropertyChange method that takes Object values.
*
* @param propertyName The programmatic name of the property
* that was changed.
* @param oldValue The old value of the property.
* @param newValue The new value of the property.
*/
public void firePropertyChange(String propertyName,
int oldValue, int newValue) {
if (oldValue == newValue) {
return;
}
firePropertyChange(propertyName, new Integer(oldValue), new Integer(newValue));
}
/**
* Report a boolean bound property update to any registered listeners.
* No event is fired if old and new are equal and non-null.
* <p>
* This is merely a convenience wrapper around the more general
* firePropertyChange method that takes Object values.
*
* @param propertyName The programmatic name of the property
* that was changed.
* @param oldValue The old value of the property.
* @param newValue The new value of the property.
*/
public void firePropertyChange(String propertyName,
boolean oldValue, boolean newValue) {
if (oldValue == newValue) {
return;
}
firePropertyChange(propertyName, Boolean.valueOf(oldValue), Boolean.valueOf(newValue));
}
/**
* Fire an existing PropertyChangeEvent to any registered listeners.
* No event is fired if the given event's old and new values are
* equal and non-null.
* @param evt The PropertyChangeEvent object.
*/
public void firePropertyChange(PropertyChangeEvent evt) {
Object oldValue = evt.getOldValue();
Object newValue = evt.getNewValue();
String propertyName = evt.getPropertyName();
if (oldValue != null && newValue != null && oldValue.equals(newValue)) {
return;
}
if (listeners != null) {
Object[] list = listeners.getListenersInternal();
for (int i = 0; i < list.length; i++) {
PropertyChangeListener target = (PropertyChangeListener)list[i];
target.propertyChange(evt);
}
}
if (children != null && propertyName != null) {
PropertyChangeSupport child = null;
child = (PropertyChangeSupport)children.get(propertyName);
if (child != null) {
child.firePropertyChange(evt);
}
}
}
/**
* Report a bound indexed property update to any registered
* listeners.
* <p>
* No event is fired if old and new values are equal
* and non-null.
*
* @param propertyName The programmatic name of the property that
* was changed.
* @param index index of the property element that was changed.
* @param oldValue The old value of the property.
* @param newValue The new value of the property.
* @since 1.5
*/
public void fireIndexedPropertyChange(String propertyName, int index,
Object oldValue, Object newValue) {
firePropertyChange(new IndexedPropertyChangeEvent
(source, propertyName, oldValue, newValue, index));
}
/**
* Report an <code>int</code> bound indexed property update to any registered
* listeners.
* <p>
* No event is fired if old and new values are equal
* and non-null.
* <p>
* This is merely a convenience wrapper around the more general
* fireIndexedPropertyChange method which takes Object values.
*
* @param propertyName The programmatic name of the property that
* was changed.
* @param index index of the property element that was changed.
* @param oldValue The old value of the property.
* @param newValue The new value of the property.
* @since 1.5
*/
public void fireIndexedPropertyChange(String propertyName, int index,
int oldValue, int newValue) {
if (oldValue == newValue) {
return;
}
fireIndexedPropertyChange(propertyName, index,
new Integer(oldValue),
new Integer(newValue));
}
/**
* Report a <code>boolean</code> bound indexed property update to any
* registered listeners.
* <p>
* No event is fired if old and new values are equal and non-null.
* <p>
* This is merely a convenience wrapper around the more general
* fireIndexedPropertyChange method which takes Object values.
*
* @param propertyName The programmatic name of the property that
* was changed.
* @param index index of the property element that was changed.
* @param oldValue The old value of the property.
* @param newValue The new value of the property.
* @since 1.5
*/
public void fireIndexedPropertyChange(String propertyName, int index,
boolean oldValue, boolean newValue) {
if (oldValue == newValue) {
return;
}
fireIndexedPropertyChange(propertyName, index, Boolean.valueOf(oldValue),
Boolean.valueOf(newValue));
}
/**
* Check if there are any listeners for a specific property, including
* those registered on all properties. If <code>propertyName</code>
* is null, only check for listeners registered on all properties.
*
* @param propertyName the property name.
* @return true if there are one or more listeners for the given property
*/
public synchronized boolean hasListeners(String propertyName) {
if (listeners != null && !listeners.isEmpty()) {
// there is a generic listener
return true;
}
if (children != null && propertyName != null) {
PropertyChangeSupport child = (PropertyChangeSupport)children.get(propertyName);
if (child != null && child.listeners != null) {
return !child.listeners.isEmpty();
}
}
return false;
}
/**
* @serialData Null terminated list of <code>PropertyChangeListeners</code>.
* <p>
* At serialization time we skip non-serializable listeners and
* only serialize the serializable listeners.
*
*/
private void writeObject(ObjectOutputStream s) throws IOException {
s.defaultWriteObject();
if (listeners != null) {
Object[] list = listeners.getListenersCopy();
for (int i = 0; i < list.length; i++) {
PropertyChangeListener l = (PropertyChangeListener)list[i];
if (l instanceof Serializable) {
s.writeObject(l);
}
}
}
s.writeObject(null);
}
private void readObject(ObjectInputStream s) throws ClassNotFoundException, IOException {
s.defaultReadObject();
Object listenerOrNull;
while (null != (listenerOrNull = s.readObject())) {
addPropertyChangeListener((PropertyChangeListener)listenerOrNull);
}
}
/**
* Hashtable for managing listeners for specific properties.
* Maps property names to PropertyChangeSupport objects.
* @serial
* @since 1.2
*/
private java.util.Hashtable children;
/**
* The object to be provided as the "source" for any generated events.
* @serial
*/
private Object source;
/**
* Internal version number
* @serial
* @since
*/
private int propertyChangeSupportSerializedDataVersion = 2;
/**
* Serialization version ID, so we're compatible with JDK 1.1
*/
static final long serialVersionUID = 6401253773779951803L;
}
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