/*
* Copyright 1996-2006 Sun Microsystems, Inc. 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. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package java.beans;
import java.io.Serializable;
import java.io.ObjectStreamField;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import java.util.Hashtable;
import java.util.Map.Entry;
/**
* This is a utility class that can be used by beans that support constrained
* 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 VetoableChangeSupport implements Serializable {
private VetoableChangeListenerMap map = new VetoableChangeListenerMap();
/**
* Constructs a <code>VetoableChangeSupport</code> object.
*
* @param sourceBean The bean to be given as the source for any events.
*/
public VetoableChangeSupport(Object sourceBean) {
if (sourceBean == null) {
throw new NullPointerException();
}
source = sourceBean;
}
/**
* Add a VetoableChangeListener 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 VetoableChangeListener to be added
*/
public void addVetoableChangeListener(VetoableChangeListener listener) {
if (listener == null) {
return;
}
if (listener instanceof VetoableChangeListenerProxy) {
VetoableChangeListenerProxy proxy =
(VetoableChangeListenerProxy)listener;
// Call two argument add method.
addVetoableChangeListener(proxy.getPropertyName(),
(VetoableChangeListener)proxy.getListener());
} else {
this.map.add(null, listener);
}
}
/**
* Remove a VetoableChangeListener from the listener list.
* This removes a VetoableChangeListener 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 VetoableChangeListener to be removed
*/
public void removeVetoableChangeListener(VetoableChangeListener listener) {
if (listener == null) {
return;
}
if (listener instanceof VetoableChangeListenerProxy) {
VetoableChangeListenerProxy proxy =
(VetoableChangeListenerProxy)listener;
// Call two argument remove method.
removeVetoableChangeListener(proxy.getPropertyName(),
(VetoableChangeListener)proxy.getListener());
} else {
this.map.remove(null, listener);
}
}
/**
* Returns the list of VetoableChangeListeners. If named vetoable change listeners
* were added, then VetoableChangeListenerProxy wrappers will returned
* <p>
* @return List of VetoableChangeListeners and VetoableChangeListenerProxys
* if named property change listeners were added.
* @since 1.4
*/
public VetoableChangeListener[] getVetoableChangeListeners(){
return this.map.getListeners();
}
/**
* Add a VetoableChangeListener for a specific property. The listener
* will be invoked only when a call on fireVetoableChange 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 VetoableChangeListener to be added
*/
public void addVetoableChangeListener(
String propertyName,
VetoableChangeListener listener) {
if (listener == null || propertyName == null) {
return;
}
listener = this.map.extract(listener);
if (listener != null) {
this.map.add(propertyName, listener);
}
}
/**
* Remove a VetoableChangeListener 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 VetoableChangeListener to be removed
*/
public void removeVetoableChangeListener(
String propertyName,
VetoableChangeListener listener) {
if (listener == null || propertyName == null) {
return;
}
listener = this.map.extract(listener);
if (listener != null) {
this.map.remove(propertyName, 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 the <code>VetoableChangeListeners</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.
* @since 1.4
*/
public VetoableChangeListener[] getVetoableChangeListeners(String propertyName) {
return this.map.getListeners(propertyName);
}
/**
* Report a vetoable property update to any registered listeners. If
* anyone vetos the change, then fire a new event reverting everyone to
* the old value and then rethrow the PropertyVetoException.
* <p>
* No event is fired if old and new are equal and non-null.
*
* @param propertyName The programmatic name of the property
* that is about to change..
* @param oldValue The old value of the property.
* @param newValue The new value of the property.
* @exception PropertyVetoException if the recipient wishes the property
* change to be rolled back.
*/
public void fireVetoableChange(String propertyName,
Object oldValue, Object newValue)
throws PropertyVetoException {
if (oldValue != null && newValue != null && oldValue.equals(newValue)) {
return;
}
PropertyChangeEvent evt = new PropertyChangeEvent(source, propertyName,
oldValue, newValue);
fireVetoableChange(evt);
}
/**
* Report a int vetoable property update to any registered listeners.
* No event is fired if old and new are equal.
* <p>
* This is merely a convenience wrapper around the more general
* fireVetoableChange method that takes Object values.
*
* @param propertyName The programmatic name of the property
* that is about to change.
* @param oldValue The old value of the property.
* @param newValue The new value of the property.
*/
public void fireVetoableChange(String propertyName,
int oldValue, int newValue)
throws PropertyVetoException {
if (oldValue == newValue) {
return;
}
fireVetoableChange(propertyName, Integer.valueOf(oldValue), Integer.valueOf(newValue));
}
/**
* Report a boolean vetoable property update to any registered listeners.
* No event is fired if old and new are equal.
* <p>
* This is merely a convenience wrapper around the more general
* fireVetoableChange method that takes Object values.
*
* @param propertyName The programmatic name of the property
* that is about to change.
* @param oldValue The old value of the property.
* @param newValue The new value of the property.
*/
public void fireVetoableChange(String propertyName,
boolean oldValue, boolean newValue)
throws PropertyVetoException {
if (oldValue == newValue) {
return;
}
fireVetoableChange(propertyName, Boolean.valueOf(oldValue), Boolean.valueOf(newValue));
}
/**
* Fire a vetoable property update to any registered listeners. If
* anyone vetos the change, then fire a new event reverting everyone to
* the old value and then rethrow the PropertyVetoException.
* <p>
* No event is fired if old and new are equal and non-null.
*
* @param evt The PropertyChangeEvent to be fired.
* @exception PropertyVetoException if the recipient wishes the property
* change to be rolled back.
*/
public void fireVetoableChange(PropertyChangeEvent evt)
throws PropertyVetoException {
Object oldValue = evt.getOldValue();
Object newValue = evt.getNewValue();
String propertyName = evt.getPropertyName();
if (oldValue != null && newValue != null && oldValue.equals(newValue)) {
return;
}
VetoableChangeListener[] common = this.map.get(null);
VetoableChangeListener[] named = (propertyName != null)
? this.map.get(propertyName)
: null;
fire(common, evt);
fire(named, evt);
}
private void fire(VetoableChangeListener[] listeners, PropertyChangeEvent event) throws PropertyVetoException {
if (listeners != null) {
VetoableChangeListener current = null;
try {
for (VetoableChangeListener listener : listeners) {
current = listener;
listener.vetoableChange(event);
}
} catch (PropertyVetoException veto) {
// Create an event to revert everyone to the old value.
event = new PropertyChangeEvent( this.source,
event.getPropertyName(),
event.getNewValue(),
event.getOldValue() );
for (VetoableChangeListener listener : listeners) {
try {
listener.vetoableChange(event);
} catch (PropertyVetoException ex) {
// We just ignore exceptions that occur during reversions.
}
}
// And now rethrow the PropertyVetoException.
throw veto;
}
}
}
/**
* 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 boolean hasListeners(String propertyName) {
return this.map.hasListeners(propertyName);
}
/**
* @serialData Null terminated list of <code>VetoableChangeListeners</code>.
* <p>
* At serialization time we skip non-serializable listeners and
* only serialize the serializable listeners.
*/
private void writeObject(ObjectOutputStream s) throws IOException {
Hashtable<String, VetoableChangeSupport> children = null;
VetoableChangeListener[] listeners = null;
synchronized (this.map) {
for (Entry<String, VetoableChangeListener[]> entry : this.map.getEntries()) {
String property = entry.getKey();
if (property == null) {
listeners = entry.getValue();
} else {
if (children == null) {
children = new Hashtable<String, VetoableChangeSupport>();
}
VetoableChangeSupport vcs = new VetoableChangeSupport(this.source);
vcs.map.set(null, entry.getValue());
children.put(property, vcs);
}
}
}
ObjectOutputStream.PutField fields = s.putFields();
fields.put("children", children);
fields.put("source", this.source);
fields.put("vetoableChangeSupportSerializedDataVersion", 2);
s.writeFields();
if (listeners != null) {
for (VetoableChangeListener l : listeners) {
if (l instanceof Serializable) {
s.writeObject(l);
}
}
}
s.writeObject(null);
}
private void readObject(ObjectInputStream s) throws ClassNotFoundException, IOException {
this.map = new VetoableChangeListenerMap();
ObjectInputStream.GetField fields = s.readFields();
Hashtable<String, VetoableChangeSupport> children = (Hashtable<String, VetoableChangeSupport>) fields.get("children", null);
this.source = fields.get("source", null);
fields.get("vetoableChangeSupportSerializedDataVersion", 2);
Object listenerOrNull;
while (null != (listenerOrNull = s.readObject())) {
this.map.add(null, (VetoableChangeListener)listenerOrNull);
}
if (children != null) {
for (Entry<String, VetoableChangeSupport> entry : children.entrySet()) {
for (VetoableChangeListener listener : entry.getValue().getVetoableChangeListeners()) {
this.map.add(entry.getKey(), listener);
}
}
}
}
/**
* The object to be provided as the "source" for any generated events.
*/
private Object source;
/**
* @serialField children Hashtable
* @serialField source Object
* @serialField propertyChangeSupportSerializedDataVersion int
*/
private static final ObjectStreamField[] serialPersistentFields = {
new ObjectStreamField("children", Hashtable.class),
new ObjectStreamField("source", Object.class),
new ObjectStreamField("vetoableChangeSupportSerializedDataVersion", Integer.TYPE)
};
/**
* Serialization version ID, so we're compatible with JDK 1.1
*/
static final long serialVersionUID = -5090210921595982017L;
/**
* This is a {@link ChangeListenerMap ChangeListenerMap} implementation
* that works with {@link VetoableChangeListener VetoableChangeListener} objects.
*/
private static final class VetoableChangeListenerMap extends ChangeListenerMap<VetoableChangeListener> {
private static final VetoableChangeListener[] EMPTY = {};
/**
* Creates an array of {@link VetoableChangeListener VetoableChangeListener} objects.
* This method uses the same instance of the empty array
* when {@code length} equals {@code 0}.
*
* @param length the array length
* @return an array with specified length
*/
@Override
protected VetoableChangeListener[] newArray(int length) {
return (0 < length)
? new VetoableChangeListener[length]
: EMPTY;
}
/**
* Creates a {@link VetoableChangeListenerProxy VetoableChangeListenerProxy}
* object for the specified property.
*
* @param name the name of the property to listen on
* @param listener the listener to process events
* @return a {@code VetoableChangeListenerProxy} object
*/
@Override
protected VetoableChangeListener newProxy(String name, VetoableChangeListener listener) {
return new VetoableChangeListenerProxy(name, listener);
}
}
}