Switching

In RxJava, there is a powerful operator called switchMap(). Its usage is similar to flatMap(), but it has one important behavioral difference: it emits the latest Observable derived from the latest emission and disposes of any previous observables that were processing. In other words, it allows you to cancel an emitting Observable and switch to a new one, thereby preventing stale or redundant processing.

If, for example, we have a process that emits nine strings, and it delays each string emission randomly from 0 to 2,000 milliseconds (emulating an intense calculation), this can be demonstrated as follows:

import io.reactivex.rxjava3.core.Observable;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeUnit;

public class Ch7_14 {
    public static void main(String[] args) {
       Observable<String> items = Observable.just("Alpha&quot...