private void register(
Adapter listener, AbstractEventFilter eventFilterTree, ListenerTypeEnum listenerType) {
// Check preconditions for parameters
if (listener == null) {
throw new IllegalArgumentException("Event listener must not be null");
}
if (eventFilterTree == null) {
throw new IllegalArgumentException("Event filter must not be null");
}
// Use WeakReference to avoid dangling registrations
WeakReference<Adapter> listenerRef =
new WeakReference<Adapter>(listener, adaptersNoLongerStronglyReferenced);
// delegate registration to RegistrationManager
// The event filter is cloned, because the calculation of the DNF will modify the filter tree
registrationManager.register(eventFilterTree.clone(), listenerRef, listenerType);
// instantiate and associate notifier
AdapterCapsule notifier = null;
if (listenerType.matches(listenersForNotifier)) {
notifier = new AdapterCapsule(listenerRef, listenerType, this);
} else if (listenerType.matches(listenersForDeferringNotifier)) {
notifier = new DeferringNotifier(listenerRef, listenerType, this);
} else {
logger.warning("Unkown listenerType " + listenerType);
}
addNotifierForListener(notifier);
}
void deregister(Reference<? extends Adapter> listenerRef) {
Adapter adapter = listenerRef.get();
if (adapter == null) {
// WeakHashMaps with adapter as key don't need to be taken care of anymore
registrationManager.deregister(listenerRef);
} else {
deregister(adapter);
}
}
/**
* This method notifies all interested listeners by invoking the fireEvent() method on their
* associated Notifier.
*
* @param event the event that will be delivered to clients
*/
private void fireEvent(Notification event) {
Collection<WeakReference<? extends Adapter>> listeners =
registrationManager.getListenersFor(event);
for (WeakReference<? extends Adapter> listenerRef : listeners) {
AdapterCapsule notifier = getNotifierForListener(listenerRef, ListenerTypeEnum.postChange);
if (notifier != null) {
notifier.fireEvent(event);
}
}
}
public String toString() {
return registrationManager.toString();
}
public void deregister(Adapter listener) {
// TODO what if a listener is being removed that has pending events?? -> EventDeferring
registrationManager.deregister(listener);
// remove Notifier(s) for listener
removeListener(listener);
}
