Learning RxJava

distinct()

The distinct() operator will emit each unique emission, but it will suppress any duplicates that follow. Equality is based on hashCode()/equals() implementation of the emitted objects. If we wanted to emit the distinct lengths of a string sequence, it could be done as follows:

import io.reactivex.Observable;public class Launcher {      public static void main(String[] args) {        Observable.just("Alpha", "Beta", "Gamma", "Delta", "Epsilon")          .map(String::length)          .distinct()          .subscribe(i -> System.out.println("RECEIVED: " + i));      }}

The output of the preceding code snippet is as follows:

RECEIVED: 5RECEIVED: 4RECEIVED: 7

Keep in mind that if you have a wide, diverse spectrum of unique values, distinct() can use a bit of memory. Imagine that ...