RxBus

Example.java

bus.publish(new TokenExpiredEvent());

bus.asObservable()
        .ofType(TokenExpiredEvent.class)
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(this::onTokenExpiredEvent);

RxBus.java

import rx.Observable;
import rx.subjects.PublishSubject;
import rx.subjects.SerializedSubject;
import rx.subjects.Subject;

public class RxBus {
    private final Subject<Object, Object> bus = new SerializedSubject<>(PublishSubject.create());

    public void publish(Object event) {
        bus.onNext(event);
    }

    public Observable<Object> asObservable() {
        return bus;
    }
}