java.beans

Class VetoableChangeSupport

public class VetoableChangeSupport extends Object implements Serializable

VetoableChangeSupport makes it easy to fire vetoable change events and handle listeners. It allows chaining of listeners, as well as filtering by property name. In addition, it will serialize only those listeners which are serializable, ignoring the others without problem. This class is thread-safe.

Since: 1.1

UNKNOWN: updated to 1.4

Constructor Summary
	VetoableChangeSupport(Object source) Create a VetoableChangeSupport to work with a specific source bean.

Method Summary
void	addVetoableChangeListener(VetoableChangeListener l) Adds a VetoableChangeListener to the list of global listeners.
void	addVetoableChangeListener(String propertyName, VetoableChangeListener l) Adds a VetoableChangeListener listening on the specified property.
void	fireVetoableChange(String propertyName, Object oldVal, Object newVal) Fire a PropertyChangeEvent containing the old and new values of the property to all the global listeners, and to all the listeners for the specified property name.
void	fireVetoableChange(String propertyName, int oldVal, int newVal) Fire a PropertyChangeEvent containing the old and new values of the property to all the global listeners, and to all the listeners for the specified property name.
void	fireVetoableChange(String propertyName, boolean oldVal, boolean newVal) Fire a PropertyChangeEvent containing the old and new values of the property to all the global listeners, and to all the listeners for the specified property name.
void	fireVetoableChange(PropertyChangeEvent event) Fire a PropertyChangeEvent to all the global listeners, and to all the listeners for the specified property name.
VetoableChangeListener[]	getVetoableChangeListeners() Returns an array of all registered vetoable change listeners.
VetoableChangeListener[]	getVetoableChangeListeners(String propertyName) Returns an array of all vetoable change listeners registered under the given property name.
boolean	hasListeners(String propertyName) Tell whether the specified property is being listened on or not.
void	removeVetoableChangeListener(VetoableChangeListener l) Removes a VetoableChangeListener from the list of global listeners.
void	removeVetoableChangeListener(String propertyName, VetoableChangeListener l) Removes a VetoableChangeListener from listening to a specific property.

Constructor Detail

VetoableChangeSupport

public VetoableChangeSupport(Object source)

Create a VetoableChangeSupport to work with a specific source bean.

Parameters: source the source bean to use

Throws: NullPointerException if source is null

Method Detail

addVetoableChangeListener

public void addVetoableChangeListener(VetoableChangeListener l)

Adds a VetoableChangeListener to the list of global listeners. All vetoable change events will be sent to this listener. The listener add is not unique: that is, n adds with the same listener will result in n events being sent to that listener for every vetoable change. This method will unwrap a VetoableChangeListenerProxy, registering the underlying delegate to the named property list.

Parameters: l the listener to add (null ignored).

addVetoableChangeListener

public void addVetoableChangeListener(String propertyName, VetoableChangeListener l)

Adds a VetoableChangeListener listening on the specified property. Events will be sent to the listener only if the property name matches. The listener add is not unique; that is, n adds on a particular property for a particular listener will result in n events being sent to that listener when that property is changed. The effect is cumulative, too; if you are registered to listen to receive events on all vetoable changes, and then you register on a particular property, you will receive change events for that property twice. This method will unwrap a VetoableChangeListenerProxy, registering the underlying delegate to the named property list if the names match, and discarding it otherwise.

Parameters: propertyName the name of the property to listen on l the listener to add

fireVetoableChange

public void fireVetoableChange(String propertyName, Object oldVal, Object newVal)

Fire a PropertyChangeEvent containing the old and new values of the property to all the global listeners, and to all the listeners for the specified property name. This does nothing if old and new are non-null and equal. If the change is vetoed, a new event is fired to notify listeners about the rollback before the exception is thrown.

Parameters: propertyName the name of the property that changed oldVal the old value newVal the new value

Throws: PropertyVetoException if the change is vetoed by a listener

fireVetoableChange

public void fireVetoableChange(String propertyName, int oldVal, int newVal)

Fire a PropertyChangeEvent containing the old and new values of the property to all the global listeners, and to all the listeners for the specified property name. This does nothing if old and new are equal. If the change is vetoed, a new event is fired to notify listeners about the rollback before the exception is thrown.

Parameters: propertyName the name of the property that changed oldVal the old value newVal the new value

Throws: PropertyVetoException if the change is vetoed by a listener

fireVetoableChange

public void fireVetoableChange(String propertyName, boolean oldVal, boolean newVal)

Fire a PropertyChangeEvent containing the old and new values of the property to all the global listeners, and to all the listeners for the specified property name. This does nothing if old and new are equal. If the change is vetoed, a new event is fired to notify listeners about the rollback before the exception is thrown.

Parameters: propertyName the name of the property that changed oldVal the old value newVal the new value

Throws: PropertyVetoException if the change is vetoed by a listener

fireVetoableChange

public void fireVetoableChange(PropertyChangeEvent event)

Fire a PropertyChangeEvent to all the global listeners, and to all the listeners for the specified property name. This does nothing if old and new values of the event are equal. If the change is vetoed, a new event is fired to notify listeners about the rollback before the exception is thrown.

Parameters: event the event to fire

Throws: NullPointerException if event is null PropertyVetoException if the change is vetoed by a listener

getVetoableChangeListeners

public VetoableChangeListener[] getVetoableChangeListeners()

Returns an array of all registered vetoable change listeners. Those that were registered under a name will be wrapped in a VetoableChangeListenerProxy, so you must check whether the listener is an instance of the proxy class in order to see what name the real listener is registered under. If there are no registered listeners, this returns an empty array.

Returns: the array of registered listeners

Since: 1.4

getVetoableChangeListeners

public VetoableChangeListener[] getVetoableChangeListeners(String propertyName)

Returns an array of all vetoable change listeners registered under the given property name. If there are no registered listeners, this returns an empty array.

Returns: the array of registered listeners

Throws: NullPointerException if propertyName is null

Since: 1.4

hasListeners

public boolean hasListeners(String propertyName)

Tell whether the specified property is being listened on or not. This will only return true if there are listeners on all properties or if there is a listener specifically on this property.

Parameters: propertyName the property that may be listened on

Returns: whether the property is being listened on

Throws: NullPointerException if propertyName is null

removeVetoableChangeListener

public void removeVetoableChangeListener(VetoableChangeListener l)

Removes a VetoableChangeListener from the list of global listeners. If any specific properties are being listened on, they must be deregistered by themselves; this will only remove the general listener to all properties. If add() has been called multiple times for a particular listener, remove() will have to be called the same number of times to deregister it. This method will unwrap a VetoableChangeListenerProxy, removing the underlying delegate from the named property list.

Parameters: l the listener to remove

removeVetoableChangeListener

public void removeVetoableChangeListener(String propertyName, VetoableChangeListener l)

Removes a VetoableChangeListener from listening to a specific property. If add() has been called multiple times for a particular listener on a property, remove() will have to be called the same number of times to deregister it. This method will unwrap a VetoableChangeListenerProxy, removing the underlying delegate from the named property list if the names match.

Parameters: propertyName the property to stop listening on l the listener to remove

Throws: NullPointerException if propertyName is null