RxJava; How to emit observables synchronously

Question

I want to synchronously emit two Observable objects (which are asynchronous), one after the other where it returns the first emitted Observable object. If the first

Answer 1

I don't know Java, but the solution in Scala would probably be this, hope it is readable to you

import rx.lang.scala.Observable

class AccessToken
class Account

case class TokenAndAccount(token: AccessToken, account: Account)

val accessTokenSource = Observable.just(new AccessToken)
val accountSource = Observable.just(new Account)

accessTokenSource
   .flatMap(token ⇒ accountSource.map(account ⇒ TokenAndAccount(token, account)))
   .subscribe(tokenAndAccount ⇒ println(tokenAndAccount))

Basically flatMap will make sure that the accountSource.map... is used only after the token from accessTokenSource has been emitted. Inside the accountSource.map we combine the obtained token and account together for later usage in subscribe.

flatMap is one of the most useful operators, be sure to read it's docs and perhaps some tutorials.