java.beans
Class VetoableChangeSupport

java.lang.Object
  java.beans.VetoableChangeSupport

All Implemented Interfaces:

Serializable

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

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 VetoableChangeListener 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.
VetoableChangeListener[]	getVetoableChangeListeners() Returns an array of all the listeners that were added to the VetoableChangeSupport object with addVetoableChangeListener().
VetoableChangeListener[]	getVetoableChangeListeners(String propertyName) Returns an array of all the listeners which have been associated with the named property.
boolean	hasListeners(String propertyName) Check if there are any listeners for a specific property, including those registered on all properties.
void	removeVetoableChangeListener(String propertyName, VetoableChangeListener listener) Remove a VetoableChangeListener for a specific property.
void	removeVetoableChangeListener(VetoableChangeListener listener) Remove a VetoableChangeListener from the listener list.

Methods inherited from class java.lang.Object

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

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 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 listener is null, no exception is thrown and no action is taken.

Parameters:

listener - The VetoableChangeListener to be added

removeVetoableChangeListener

public void removeVetoableChangeListener(VetoableChangeListener listener)

Remove a VetoableChangeListener from the listener list. This removes a VetoableChangeListener that was registered for all properties. If listener was added more than once to the same event source, it will be notified one less time after being removed. If listener is null, or was never added, no exception is thrown and no action is taken.

Parameters:

listener - The VetoableChangeListener to be removed

getVetoableChangeListeners

public VetoableChangeListener[] getVetoableChangeListeners()

Returns an array of all the listeners that were added to the VetoableChangeSupport object with addVetoableChangeListener().

If some listeners have been added with a named property, then the returned array will be a mixture of VetoableChangeListeners and VetoableChangeListenerProxys. If the calling method is interested in distinguishing the listeners then it must test each element to see if it's a VetoableChangeListenerProxy, perform the cast, and examine the parameter.

 VetoableChangeListener[] listeners = bean.getVetoableChangeListeners();
 for (int i = 0; i < listeners.length; i++) {
        if (listeners[i] instanceof VetoableChangeListenerProxy) {
     VetoableChangeListenerProxy proxy =
                    (VetoableChangeListenerProxy)listeners[i];
     if (proxy.getPropertyName().equals("foo")) {
       // proxy is a VetoableChangeListener which was associated
       // with the property named "foo"
     }
   }
 }

Returns:

all of the VetoableChangeListeners added or an empty array if no listeners have been added

Since:

1.4

See Also:

VetoableChangeListenerProxy

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. 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 propertyName or listener is null, no exception is thrown and no action is taken.

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. If listener 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 propertyName is null, no exception is thrown and no action is taken. If listener is null, or was never added for the specified property, no exception is thrown and no action is taken.

Parameters:

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

listener - The VetoableChangeListener to be removed

getVetoableChangeListeners

public VetoableChangeListener[] getVetoableChangeListeners(String propertyName)

Returns an array of all the listeners which have been associated with the named property.

Parameters:

propertyName - The name of the property being listened to

Returns:

all the VetoableChangeListeners associated with the named property. If no such listeners have been added, or if propertyName is null, an empty array is returned.

Since:

1.4

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.

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.

Throws:

PropertyVetoException

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.

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.

Throws:

PropertyVetoException

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, including those registered on all properties. If propertyName is null, only check for listeners registered on all properties.

Parameters:

propertyName - the property name.

Returns:

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