org.jutil.event
Interface NullEventReliancy

All Superinterfaces:

ListenerValidity, Notifier

public interface NullEventReliancy

extends Notifier

This model type extends the Notifier contract, stating that only null is valid as event.

If your notifier only accepts null as valid events, you can simply model implement this type to inherit that contract. The implementation of Notifier#notifyListner(EventListener, EventObject) then can depend on the fact that it's event argument will be null, because this method is used as an abstract precondition. This extra contract will never be used, because a notifier that knows the event will be null, will never use the argument anyway, and thus does not rely on the actual value of the formal argument event. Any extra information about it is irrelevant.

Field Summary
static java.lang.String	CVS_REVISION

 

Method Summary
abstract  boolean	isValidEvent(java.util.EventObject event)           If event is not null, this method will return false.

 

Methods inherited from interface org.jutil.event.Notifier

notifyEventListener, notifyEventListenerCalled

 

Methods inherited from interface org.jutil.event.ListenerValidity

isValidListener

 

Field Detail

CVS_REVISION

public static final java.lang.String CVS_REVISION

isValidEvent

public abstract boolean isValidEvent(java.util.EventObject event)

If event is not null, this method will return false. If event is null, this method will return true. There is nothing more regarding the event that subtypes can demand.

Specifications: pure

     also

public behavior
ensures \result <==> (event == null);

Specifications inherited from overridden method in interface Notifier:
      --- None ---