Read object values from Observable

Question

Is there a way I can return user list from userObservable in the below code. Basically how to read object values of an Observable.

public List<User> getUserList(){
    Observable<Map<String, Object>> userDetailsObservable = getUserDetails(...);
    Observable<Map<String, Object>> userLikesObservable = getUserLikes(...);
    Observable<List<User>> userObservable = Observable.zip(userDetailsObservable,
            userLikesObservable, new Func2<Map<String, Object>, Map<String, Object>, List<User>>() {
                public List<User> call(Map<String, Object> value1, Map<String, Object> value2) {
                    List<User> userList = new ArrayList<User>();
                    //Iterating both maps and composing user list here.
                    return userList;
                }
            });
    userObservable.subscribe(new Subscriber<List<User>>() {
        @Override
        public void onNext(List<User> userList) {
            System.out.println("Merged values " + userList);
        }

        @Override
        public void onError(Throwable error) {
            System.err.println("Error: " + error.getMessage());
        }

        @Override
        public void onCompleted() {
            System.out.println("Sequence complete.");
        }
    });
    // Throws ClassCastException which is expected... How do I get the user list from userObservable
    List<User> userList = List<User> userObservable;

    return userList; //Fetch the user list from userObservable and return
}

Answer 1

You need to subscribe to the userObservable. You will then get a list of users emitted when the data becomes available.

userObservable
    .subscribe(users -> {
        for (User user : users) {
            // Do what you want with user.
        }
    });

EDIT: To return the list you would need to use a toBlocking() call. Then you can use one of the Blocking Observable Operators to get the desired effect. Most likely first() or single() will work for you.

return userObservable
    .toBlocking()
    .first();