Schedulers.from(Executor) method converts an Executor into a new Scheduler instance.
Create the following Java program using any editor of your choice in, say, C:\> RxJava.
import java.util.Random; import java.util.concurrent.Executors; import io.reactivex.Observable; import io.reactivex.schedulers.Schedulers; public class ObservableTester { public static void main(String[] args) throws InterruptedException { Observable.just("A", "AB", "ABC") .flatMap(v -> getLengthWithDelay(v) .doOnNext(s -> System.out.println("Processing Thread " + Thread.currentThread().getName())) .subscribeOn(Schedulers.from(Executors.newFixedThreadPool(3)))) .subscribe(length -> System.out.println("Receiver Thread " + Thread.currentThread().getName() + ", Item length " + length)); Thread.sleep(10000); } protected static Observable<Integer> getLengthWithDelay(String v) { Random random = new Random(); try { Thread.sleep(random.nextInt(3) * 1000); return Observable.just(v.length()); } catch (InterruptedException e) { e.printStackTrace(); } return null; } }
Compile the class using javac compiler as follows −
C:\RxJava>javac ObservableTester.java
Now run the ObservableTester as follows −
C:\RxJava>java ObservableTester
It should produce the following output −
Processing Thread pool-1-thread-1 Processing Thread pool-3-thread-1 Receiver Thread pool-1-thread-1, Item length 1 Processing Thread pool-4-thread-1 Receiver Thread pool-4-thread-1, Item length 3 Receiver Thread pool-3-thread-1, Item length 2