Easy to use implementation of observer pattern.
Observable
class Observable {
@Subject
Observers<Event> observers;
public Observable() {
MetaHelper.createObservable(this);
}
}
Through observers you can fire an event:
remove all observers:
or both:
observers.notifyAndClear(event);
Observer
To create an Observer, put @Observe annotation on the method that accepts one parameter - Event class.
class Observer {
private ObserverHandler handler;
public Observer(Observable observable) {
handler = MetaHelper.registerObserver(this, observable);
}
@Observe(Observable.class)
void onEvent(Event event) {
}
}
Note If you use an observable that extends Observable, you need to explicitly define the class of observable that fires the event: MetaHelper.registerObserver(this, observable, Observable.class);.
The handler allows you to detach Observer from Observable:
handler.unregisterAll(Observable.class);
Stop listening to a certain event:
handler.unregister(Event.class);
You can use one handler to control many Observables:
handler.add(MetaHelper.registerObserver(this, otherObservable));
And unregister all the listeners at once:
public static void createObservable(Object master) {
new ObservableController<>(metasitory, master).createObservable();
}
public static ObserverHandler registerObserver(Object observer, Object observable) {
return new ObserverController<>(metasitory, observer).registerObserver(observable);
}
public static ObserverHandler registerObserver(Object observer, Object observable, Class cls) {
return new ObserverController<>(metasitory, observer).registerObserver(observable, cls);
}
Please, read this article if you have questions about MetaHelper.
You should also look at Event-Bus features in addition to this guide.
