Android Flux Pattern with Otto cf. http://lgvalle.github.io/2015/08/04/flux-architecture/

EventAction.java

/**
 * Action interface
 */
public abstract class EventAction {
}

EventEmitter.java

public class EventEmitter {
  private static final Bus BUS = new Bus();
  private EventEmitter() {}

  private static class SingletonHolder {
      private static final EventEmitter instance = new EventEmitter();
  }

  public static EventEmitter get() {
      return SingletonHolder.instance;
  }

  public void on(Object obj) {
      BUS.register(obj);
  }

  public void off(Object obj) {
      BUS.unregister(obj);
  }

  public void emit(EventAction action) {
      post(action);
  }

  /**
   * Post Action in UI Thread.
   */
  private void post(final EventAction action) {
      new Handler(Looper.getMainLooper()).post(new Runnable() {
          @Override
          public void run() {
              BUS.post(action);
          }
      });
  }
}

EventStore.java

public abstract class EventStore {
 
  private final EventEmitter eventEmitter;
 
  protected EventStore(EventEmitter eventEmitter) {
      this.eventEmitter = eventEmitter;
  }
 
  /**
   * Action emitted when this store changed.
   */
  protected abstract StoreChangeAction changeStoreAction();
 
  /**
   * emit self
   */
  protected void emitSelf() {
      eventEmitter.emit(changeStoreAction());
  }
 
  /**
   * Handling Action
   */
  protected abstract void onAction(EventAction action);
}

StoreChangeAction.java

public class StoreChangeAction<T extends EventStore> implements EventAction {

  private T store;

  public StoreChangeAction(T store) {
      this.store = store;
  }

  public T getStore() {
      return store;
  }
}