Learning RxJava - Second Edition

ReplaySubject

The ReplaySubject class behaves similar to PublishSubject followed by a cache() operator. It immediately captures emissions regardless of the presence of a downstream Observer and optimizes the caching to occur inside the Subject itself. Here is an example:

import io.reactivex.rxjava3.subjects.ReplaySubject;import io.reactivex.rxjava3.subjects.Subject;public class Ch5_19 {    public static void main(String[] args) {        Subject<String> subject = ReplaySubject.create();        subject.subscribe(s -> System.out.println("Observer 1: " + s));        subject.onNext("Alpha");        subject.onNext("Beta");        subject.onNext("Gamma");        subject.onComplete();        subject.subscribe(s -> System.out.println("Observer 2: " + s));    }}

The output obtained is as follows:

Observer ...