I have two observables.
First - get session from internet or from cache;
Observable<SessionKey> getSession = getSessionFromInternetOrCache();
Second - call to server api, using session
Observable<MyResult> apiCall = getSession.flatMap(session -> {
return myApi.getResult(session);
})
Problem, that I have several independent components (gui). They are starting in parallel. apiCall
also started in parallel. And i gets several session keys.
What behavior I want: getSessions
should calling once, other observables waiting first getSessions
call. After first getSessions
calling, all getSessions
will be return cached session;
What idea to implement that behaviour?
UPD Behavior should be: Retrieving session from internet should block other getSessions calls, until session not will be cached.
You can call
cache()
on the returned Observable ingetSessionFromInternetOrCache
and it will make sure the session will be retrieved only once and replayed to anyone trying to observe it later. I assume the actual session retrieval only happens when one subscribes to the Observable.Edit: this example shows what I meant: