Syntax error How can we implement the SubmissionPublisher class in Java 9?

How can we implement the SubmissionPublisher class in Java 9?

Since Java 9, we can create Reactive Streams by introducing four core interfaces: Publisher, Subscriber, Subscription, Processor, and one concrete class: SubmissionPublisher that implements the Publisher interface. Each interface plays a different role, corresponding to the principles of Reactive Streams. We can use the submit() method of SubmissionPublisher class to publish the provided item to each subscriber.

Syntax

public class SubmissionPublisher<T> extends Object implements Flow.Publisher<T>, AutoCloseable

In the below example, we can implement the SubmissionPublisher class

Example

import java.util.concurrent.Flow.Subscriber;
import java.util.concurrent.Flow.Subscription;
import java.util.concurrent.SubmissionPublisher;

class MySubscriber<T> implements Subscriber<T> {
   private Subscription subscription;
   private String name;
   public MySubscriber(String name) {
      this.name = name;
   }
   @Override
   public void onComplete() {
      System.out.println(name + ": onComplete");
   }
   @Override
   public void onError(Throwable t) {
      System.out.println(name + ": onError");
      t.printStackTrace();
   }
   @Override
   public void onNext(T msg) {
      System.out.println(name + ": " + msg.toString() + " received in onNext");
      subscription.request(1);
   }
   @Override
   public void onSubscribe(Subscription subscription) {
      System.out.println(name + ": onSubscribe");
      this.subscription = subscription;
      subscription.request(1);
   }
}

// Main class
public class FlowTest {
   public static void main(String args[]) {
      SubmissionPublisher<String> publisher = new SubmissionPublisher<>();
      MySubscriber<String> subscriber = new MySubscriber<>("Mine");
      MySubscriber<String> subscriberYours = new MySubscriber<>("Yours");
      MySubscriber<String> subscriberHis = new MySubscriber<>("His");
      MySubscriber<String> subscriberHers = new MySubscriber<>("Her");

      publisher.subscribe(subscriber);
      publisher.subscribe(subscriberYours);
      publisher.subscribe(subscriberHis);
      publisher.subscribe(subscriberHers);

      publisher.submit("One");
      publisher.submit("Two");
      publisher.submit("Three");
      publisher.submit("Four");
      publisher.submit("Five");

      try {
         Thread.sleep(1000);
      } catch(InterruptedException e) {
         e.printStackTrace();
      }
      publisher.close();
   }
}

Output

Yours: onSubscribe
His: onSubscribe
Mine: onSubscribe
His: One received in onNext
Yours: One received in onNext
Mine: One received in onNext
Yours: Two received in onNext
His: Two received in onNext
Yours: Three received in onNext
Mine: Two received in onNext
Yours: Four received in onNext
His: Three received in onNext
Yours: Five received in onNext
Mine: Three received in onNext
Her: onSubscribe
His: Four received in onNext
Her: One received in onNext
Mine: Four received in onNext
Her: Two received in onNext
His: Five received in onNext
Her: Three received in onNext
Mine: Five received in onNext
Her: Four received in onNext
Her: Five received in onNext
Yours: onComplete
His: onComplete
Mine: onComplete
Her: onComplete
Updated on: 2020-03-09T09:45:11+05:30

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