java.beans
Class VetoableChangeSupport

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

public class VetoableChangeSupport

extends Object

implements Serializable

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.

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.
(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.
private int	vetoableChangeSupportSerializedDataVersion Internal version number

Constructor Summary

VetoableChangeSupport(Object sourceBean)
Constructs a VetoableChangeSupport object.

Method Summary

void	addVetoableChangeListener(String propertyName, VetoableChangeListener listener) Add a VetoableChangeListener for a specific property.
void	addVetoableChangeListener(VetoableChangeListener listener) Add a VetoableListener to the listener list.
void	fireVetoableChange(PropertyChangeEvent evt) Fire a vetoable property update to any registered listeners.
void	fireVetoableChange(String propertyName, boolean oldValue, boolean newValue) Report a boolean vetoable property update to any registered listeners.
void	fireVetoableChange(String propertyName, int oldValue, int newValue) Report a int vetoable property update to any registered listeners.
void	fireVetoableChange(String propertyName, Object oldValue, Object newValue) Report a vetoable 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	removeVetoableChangeListener(String propertyName, VetoableChangeListener listener) Remove a VetoableChangeListener for a specific property.
void	removeVetoableChangeListener(VetoableChangeListener listener) Remove a VetoableChangeListener from the listener list.
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 VetoableChangeSupport objects.

Since:

JDK 1.2

source

private Object source

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

vetoableChangeSupportSerializedDataVersion

private int vetoableChangeSupportSerializedDataVersion

Internal version number

serialVersionUID

static final long serialVersionUID

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

Constructor Detail

VetoableChangeSupport

public VetoableChangeSupport(Object sourceBean)

Constructs a VetoableChangeSupport object.

Parameters:

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

Method Detail

addVetoableChangeListener

public void addVetoableChangeListener(VetoableChangeListener listener)

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

Parameters:

listener - The VetoableChangeListener to be added

removeVetoableChangeListener

public void removeVetoableChangeListener(VetoableChangeListener listener)

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

Parameters:

listener - The VetoableChangeListener to be removed

addVetoableChangeListener

public void addVetoableChangeListener(String propertyName,
                                      VetoableChangeListener listener)

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

Parameters:

propertyName - The name of the property to listen on.

listener - The VetoableChangeListener to be added

removeVetoableChangeListener

public void removeVetoableChangeListener(String propertyName,
                                         VetoableChangeListener listener)

Remove a VetoableChangeListener for a specific property.

Parameters:

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

listener - The VetoableChangeListener to be removed

fireVetoableChange

public void fireVetoableChange(String propertyName,
                               Object oldValue,
                               Object newValue)
                        throws PropertyVetoException

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.

No event is fired if old and new are equal and non-null.

Parameters:

propertyName - The programmatic name of the property that is about to change..

oldValue - The old value of the property.

newValue - The new value of the property.

Throws:

PropertyVetoException - if the recipient wishes the property change to be rolled back.

fireVetoableChange

public void fireVetoableChange(String propertyName,
                               int oldValue,
                               int newValue)
                        throws PropertyVetoException

Report a int vetoable 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 fireVetoableChange method that takes Object values.

Parameters:

propertyName - The programmatic name of the property that is about to change.

oldValue - The old value of the property.

newValue - The new value of the property.

fireVetoableChange

public void fireVetoableChange(String propertyName,
                               boolean oldValue,
                               boolean newValue)
                        throws PropertyVetoException

Report a boolean vetoable 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 fireVetoableChange method that takes Object values.

Parameters:

propertyName - The programmatic name of the property that is about to change.

oldValue - The old value of the property.

newValue - The new value of the property.

fireVetoableChange

public void fireVetoableChange(PropertyChangeEvent evt)
                        throws PropertyVetoException

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.

No event is fired if old and new are equal and non-null.

Parameters:

evt - The PropertyChangeEvent to be fired.

Throws:

PropertyVetoException - if the recipient wishes the property change to be rolled back.

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 one or more listeners for the given property

writeObject

private void writeObject(ObjectOutputStream s)
                  throws IOException

readObject

private void readObject(ObjectInputStream s)
                 throws ClassNotFoundException,
                        IOException