
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