我們如何在Java 9中使用發布-訂閱模式來實作Flow API呢？

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

public class FlowAPITest {
   public static void main(String args[]) {
      <strong>Publisher<Integer></strong> publisherSync = new <strong>Publisher<Integer></strong>() {   <strong>// Create publisher</strong>
         <strong>@Override</strong>
         public void <strong>subscribe</strong>(Subscriber<? super Integer><!--? super Integer--> subscriber) {
            for(int i = 0; i < 10; i++) {
               System.out.println(Thread.currentThread().getName() + " | Publishing = " + i);
               subscriber.<strong>onNext</strong>(i);
            }
            subscriber.<strong>onComplete</strong>();
         }
      };
      <strong>Subscriber<Integer></strong> subscriberSync = new <strong>Subscriber<Integer></strong>() {   <strong>// Create subscriber</strong>
         <strong>@Override</strong>
         public void <strong>onSubscribe</strong>(Subscription subscription) {
         }
         <strong>@Override</strong>
         public void <strong>onNext</strong>(Integer item) {
            System.out.println(Thread.currentThread().getName() + " | Received = " + item);
            try {
               Thread.sleep(100);
            } catch(InterruptedException e) {
               e.printStackTrace();
            }
         }
         <strong>@Override</strong>
         public void <strong>onError</strong>(Throwable throwable) {
         }
         <strong>@Override</strong>
         public void <strong>onComplete()</strong> {
         }
      };
      publisherSync.<strong>subscribe</strong>(subscriberSync);
   }
}

<strong>main | Publishing = 0
main | Received = 0
main | Publishing = 1
main | Received = 1
main | Publishing = 2
main | Received = 2
main | Publishing = 3
main | Received = 3
main | Publishing = 4
main | Received = 4
main | Publishing = 5
main | Received = 5
main | Publishing = 6
main | Received = 6
main | Publishing = 7
main | Received = 7
main | Publishing = 8
main | Received = 8
main | Publishing = 9
main | Received = 9</strong>