Add a VetoableChangeListener for a specific property.

  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

  Add a VetoableListener to the listener list.

  Add a VetoableListener 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

  Fire a vetoable property update to any registered listeners.

  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.

  Report a boolean vetoable property update to any registered listeners.

  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.

  Report a int vetoable property update to any registered listeners.

  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.

  Report a vetoable property update to any registered listeners.

  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.

  Returns the list of VetoableChangeListeners.

  Returns the list of VetoableChangeListeners. If named vetoable change listeners were added, then VetoableChangeListenerProxy wrappers will returned

Returns: List of VetoableChangeListeners and VetoableChangeListenerProxys if named property change listeners were added.
Since: 1.4

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

  Returns an array of all the listeners which have been associated
with the named property.
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.
Parameters:
- propertyName - The name of the property being listened to
Since: 1.4

  Check if there are any listeners for a specific property, including those registered on all properties.

  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.
Returns: true if there are one or more listeners for the given property
Parameters:
- propertyName - the property name.

  Remove a VetoableChangeListener for a specific property.

  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

  Remove a VetoableChangeListener from the listener list.

  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