gistfile1.java

/** 
 * Use case: okay lets say i have 2 separate services, one for authentication and the other for loading profile data. 
 * so can you write me some code that will : 
 * handle a login http request, asynchronously authenticate the user with a 
 * user / pass (which returns a user identifier or fails), 
 * upon success will then retrieve the profile details of the user using the id asynchronously, 
 * then output the profile details to a http response.
 */
interface APIs {
  // for simplicity am shoving these on the same API
  Future<AuthenticateResponse> authenticate(String user, String pwd);

  Future<ProfileDetails> getProfileDetails(String user);
}

APIs api = ...;
Observable<AuthenticateResponse> authObs = Observers.toObserver(api.authenticate("foo", "bar"));

Observable<ProfileDetails> profileDetailsObj = authObs.mapMany( authResp -> 
     Observers.toObserver(api.getProfileDetails(authResp.getUser())) );

// helper function to subscribe to the observable and 
// when it completes, write the state to the http request
httpResponse.marshal(profileDetailsObj);