FlatMapObservableDemo.java

package com.charter.aesd.deviceactivation.middle.rest;

import rx.Observable;

import java.util.Optional;

/**
 * Created by rhasija on 10/28/15.
 */
public class ObservableTest {

    public static void main(String[] args) {
        final Observable<Optional<Integer>> observable1 = Observable.just(Optional.of(1));
        final Observable<Optional<Integer>> observable2 = Observable.just(Optional.of(2));
        final Observable<Optional<Integer>> observable3 = Observable.just(Optional.of(3));

        final Optional<Integer> single = observable1.flatMap(integer -> {
            if (integer.get() != 1) {
                return Observable.just(integer);
            } else {
                return observable2;
            }
        }).flatMap(integer -> {
            if (integer.get() != 2) {
                return Observable.just(integer);
            } else {
                return observable3;
            }
        }).toBlocking().single();

        if (single.get() == 3) {
            System.out.println("PASSED");
        }
    }
}