[CXF-6833] support RxJava Observable<T> in return values as a more composeable alternative to Future<T>

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.2.0
• Component/s: JAX-RS
• Estimated Complexity: Unknown
• Assignee: Sergey Beryozkin
• Reporter: James Strachan
• Created: 16/Mar/16 09:14
• Updated: 28/Nov/17 10:42
• Resolved: 13/Oct/16 16:15

Description

when invoking multiple REST services concurrently in a microservice kinda world it can be really helpful to use RxJava's Observable<T> so that you can easily compose concurrent asynchronous requests together.

e.g. see this blog:
http://joluet.github.io/blog/2014/07/07/rxjava-retrofit/

Its basically about using RxJava's Observable<T> as the result type; which is a little like a Future<T> but can handle streams of values and is composable.

It would be great to do this both on the client and server side; as a server may invoke multiple asynchronous back ends and return a composition of results etc.
e.g.

@GET("/session.json")
Observable<LoginResponse> login();

@GET("/user.json")
Observable<UserState> getUserState();

you can then use the Observable<T> composition methods to join / flatMap to compose multiple requests across different microservice invocations together with timeouts etc e.g. to compose the latest from 2 calls:

Observable.combineLatest(api.fetchUserProfile(), api.getUserState(),
(user, userStatus) -> new Pair<>(user, userStatus));

and you're done! There's support for timeouts and other kinds of composition mechanisms too.