public interface VetoObserver
VetoObserver interface defines the notification API through 
 which interested observers are notified of pending subject changes.
 VetoObservers can the indicate that they do not accept
 the pending change.UpdateMessage, 
VetoableSubject| Modifier and Type | Method and Description | 
|---|---|
void | 
vetoableUpdate(java.lang.Object observed,
              UpdateMessage change)
Notification message. 
 | 
void vetoableUpdate(java.lang.Object observed,
                  UpdateMessage change)
                    throws ChangeVetoException
observed - the subject whose state has changed.change - what has changed.ChangeVetoException - if the pending update is rejected by
 the vetoableUpdate implementation.