nikosrig / event-dispatcher

Library for dispatching events

Event Dispatcher

Lightweight library for dispatching async and sync events

Installation

<dependency>
  <groupId>io.github.nikosrig</groupId>
  <artifactId>event-dispatcher</artifactId>
  <version>1.0.0</version>
</dependency>

Events

Events are objects that act as the unit of communication between an emitter and the appropriate event listeners.

public class EventExample implements Event {

	private final ArrayList<String> data = new ArrayList<>();

	public EventExample(String exampleParam) {
		this.data.add(exampleParam);
	}

	public ArrayList<String> getData() {
		return this.data;
	}

	public String getName() {
		return "example-event";
	}
}

Event Listeners

Event listeners are classes that handle the events and are triggered by event dispatchers.

public class EventListenerExample implements EventListener {
	public void handle(Event event) {
		if (!(event instanceof EventExample)) {
			return;
		}

		System.out.println("Event handling");
	}
}

Listener Providers

Listener providers act as groups of event listeners.

public class ListenerProviderExample implements ListenerProvider {

	@Override
	public ArrayList<EventListener> getListenersForEvent(Event event) {
		ArrayList<EventListener> eventListeners = new ArrayList<>();

		if (!(event instanceof EventExample)) {
			return eventListeners;
		}

		eventListeners.add(new EventListenerExample());
		return eventListeners;
	}
}

Event dispatchers

Event dispatchers are a service objects implementing EventDispatcher. They are responsible for retrieving event listeners from listener providers for the dispatched event, and invoking each event listener with that Event.

SyncEventDispatcher example

		SyncEventDispatcher syncEventDispatcher = new SyncEventDispatcher();
		syncEventDispatcher.addListener("testEvent", eventListener);
		syncEventDispatcher.addListenerProvider(listenerProvider);
		syncEventDispatcher.dispatch(event);

AsyncEventDispatcher example

		AsyncEventDispatcher asyncEventDispatcher = new AsyncEventDispatcher();
		asyncEventDispatcher.addListener("testEvent", eventListener);
		asyncEventDispatcher.addListenerProvider(listenerProvider);
		asyncEventDispatcher.dispatch(event);

🤝 Contact

Nikos Rigas - [email protected]

Licence

Distributed under the MIT License