java.beans
Class PropertyChangeSupport

java.lang.Object
  |
  +--java.beans.PropertyChangeSupport

public class PropertyChangeSupport

extends Object

implements Serializable

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.

See Also:

Serialized Form

Field Summary

private Hashtable	children Hashtable for managing listeners for specific properties.
private Vector	listeners "listeners" lists all the generic listeners.
private int	propertyChangeSupportSerializedDataVersion Internal version number
(package private) static long	serialVersionUID Serialization version ID, so we're compatible with JDK 1.1
private Object	source The object to be provided as the "source" for any generated events.

Constructor Summary

PropertyChangeSupport(Object sourceBean)
Constructs a PropertyChangeSupport object.

Method Summary

void	addPropertyChangeListener(PropertyChangeListener listener) Add a PropertyChangeListener to the listener list.
void	addPropertyChangeListener(String propertyName, PropertyChangeListener listener) Add a PropertyChangeListener for a specific property.
void	firePropertyChange(PropertyChangeEvent evt) Fire an existing PropertyChangeEvent to any registered listeners.
void	firePropertyChange(String propertyName, boolean oldValue, boolean newValue) Report a boolean bound property update to any registered listeners.
void	firePropertyChange(String propertyName, int oldValue, int newValue) Report an int bound property update to any registered listeners.
void	firePropertyChange(String propertyName, Object oldValue, Object newValue) Report a bound property update to any registered listeners.
boolean	hasListeners(String propertyName) Check if there are any listeners for a specific property.
private void	readObject(ObjectInputStream s)
void	removePropertyChangeListener(PropertyChangeListener listener) Remove a PropertyChangeListener from the listener list.
void	removePropertyChangeListener(String propertyName, PropertyChangeListener listener) Remove a PropertyChangeListener for a specific property.
private void	writeObject(ObjectOutputStream s)

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait

Field Detail

listeners

private transient Vector listeners

"listeners" lists all the generic listeners. This is transient - its state is written in the writeObject method.

children

private Hashtable children

Hashtable for managing listeners for specific properties. Maps property names to PropertyChangeSupport objects.

Since:

JDK 1.2

source

private Object source

The object to be provided as the "source" for any generated events.

propertyChangeSupportSerializedDataVersion

private int propertyChangeSupportSerializedDataVersion

Internal version number

Since:

serialVersionUID

static final long serialVersionUID

Serialization version ID, so we're compatible with JDK 1.1

Constructor Detail

PropertyChangeSupport

public PropertyChangeSupport(Object sourceBean)

Constructs a PropertyChangeSupport object.

Parameters:

sourceBean - The bean to be given as the source for any events.

Method Detail

addPropertyChangeListener

public void addPropertyChangeListener(PropertyChangeListener listener)

Add a PropertyChangeListener to the listener list. The listener is registered for all properties.

Parameters:

listener - The PropertyChangeListener to be added

removePropertyChangeListener

public void removePropertyChangeListener(PropertyChangeListener listener)

Remove a PropertyChangeListener from the listener list. This removes a PropertyChangeListener that was registered for all properties.

Parameters:

listener - The PropertyChangeListener to be removed

addPropertyChangeListener

public void addPropertyChangeListener(String propertyName,
                                      PropertyChangeListener listener)

Add a PropertyChangeListener for a specific property. The listener will be invoked only when a call on firePropertyChange names that specific property.

Parameters:

propertyName - The name of the property to listen on.

listener - The PropertyChangeListener to be added

removePropertyChangeListener

public void removePropertyChangeListener(String propertyName,
                                         PropertyChangeListener listener)

Remove a PropertyChangeListener for a specific property.

Parameters:

propertyName - The name of the property that was listened on.

listener - The PropertyChangeListener to be removed

firePropertyChange

public void firePropertyChange(String propertyName,
                               Object oldValue,
                               Object newValue)

Report a bound property update to any registered listeners. No event is fired if old and new are equal and non-null.

Parameters:

propertyName - The programmatic name of the property that was changed.

oldValue - The old value of the property.

newValue - The new value of the property.

firePropertyChange

public void firePropertyChange(String propertyName,
                               int oldValue,
                               int newValue)

Report an int bound property update to any registered listeners. No event is fired if old and new are equal and non-null.

This is merely a convenience wrapper around the more general firePropertyChange method that takes Object values.

Parameters:

propertyName - The programmatic name of the property that was changed.

oldValue - The old value of the property.

newValue - The new value of the property.

firePropertyChange

public void firePropertyChange(String propertyName,
                               boolean oldValue,
                               boolean newValue)

Report a boolean bound property update to any registered listeners. No event is fired if old and new are equal and non-null.

This is merely a convenience wrapper around the more general firePropertyChange method that takes Object values.

Parameters:

propertyName - The programmatic name of the property that was changed.

oldValue - The old value of the property.

newValue - The new value of the property.

firePropertyChange

public void firePropertyChange(PropertyChangeEvent evt)

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.

Parameters:

evt - The PropertyChangeEvent object.

hasListeners

public boolean hasListeners(String propertyName)

Check if there are any listeners for a specific property.

Parameters:

propertyName - the property name.

Returns:

true if there are ore or more listeners for the given property

writeObject

private void writeObject(ObjectOutputStream s)
                  throws IOException

readObject

private void readObject(ObjectInputStream s)
                 throws ClassNotFoundException,
                        IOException