Create a single value Observable from a Guava ListenableFuture.

gistfile1.java

  public static <T> Observable<T> create(ListenableFuture<T> future, Executor executor) {
    AsyncSubject<T> subject = AsyncSubject.create();
    future.addListener(() -> {
      try {
        T value = future.get();
        subject.onNext(value);
        subject.onCompleted();
      } catch (Exception e) {
        subject.onError(e);
      }
    }, executor);
    return subject;
  }

  public static <T> Observable<T> create(ListenableFuture<T> future) {
    return create(future, MoreExecutors.sameThreadExecutor());
  }