Examples with SubmissionPublisher java.util.concurrent.SubmissionPublisher used on opensource projects

Example 11 with SubmissionPublisher

use of java.util.concurrent.SubmissionPublisher in project java-course by bwhyman.

the class FlowTest method test.

/**
 * 为什么是发布者关联订阅者呢？
 * 事件通知架构，例如android，是订阅者关联发布者，发布者不关心订阅者，为什么flow倒置了关系？
 * 由消费者控制生产者的生产速度，这样才能支持背压Backpressure
 *
 * @throws InterruptedException
 */
private static void test() throws InterruptedException {
    // 用于在消息全部消费前阻塞主线程，避免异步下主线程结束而关闭控制台
    final CountDownLatch latch = new CountDownLatch(1);
    // 基于java自带的类创建消息发布者publisher
    SubmissionPublisher<Integer> publisher = new SubmissionPublisher<>();
    // 直接基于接口创建匿名类。创建消息订阅者subscriber
    Flow.Subscriber<Integer> subscriber = new Flow.Subscriber<>() {

        private Flow.Subscription subscription;

        // 订阅成功回调onSubscribe()方法，并注入订阅对象subscription
        @Override
        public void onSubscribe(Flow.Subscription subscription) {
            this.subscription = subscription;
            // 自动创建线程，在子线程中异步消费消息
            System.out.println("Subscriber Thread: " + Thread.currentThread().getName());
            // 通知订阅对象subscription，让发布者publisher生产一个消息
            subscription.request(1);
        }

        // 发布者publisher发布消息后，订阅者subscriber回调
        @Override
        public void onNext(Integer i) {
            // 模拟消费订阅的消息
            System.out.println("onNext: " + i);
            try {
                Thread.sleep(300);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            // 消费后继续通过订阅对象，向发布者publisher要一个消息
            subscription.request(1);
        }

        @Override
        public void onError(Throwable throwable) {
        }

        // 发布者publisher宣布不再生产消息，例如发布者调用close()方法关闭
        @Override
        public void onComplete() {
            // 通知阻塞的主线程继续运行
            latch.countDown();
        }
    };
    System.out.println("Running Thread: " + Thread.currentThread().getName());
    // 发布者publisher关联订阅者subscriber，要求subscriber以异步订阅
    publisher.subscribe(subscriber);
    // subscriber消费消息释放缓存空间后，publisher再次发布消息，直至缓存再次填满
    for (int i = 0; i < 300; i++) {
        // publisher发布消息，通知subscriber回调onNext()方法消费消息
        publisher.submit(i);
        System.out.println(i);
    }
    // publisher结束消息的发布，通知subscriber回调onComplete()方法
    publisher.close();
    // 主线程阻塞，确保subscriber异步消费消息时，
    latch.await();
}

Example 12 with SubmissionPublisher

use of java.util.concurrent.SubmissionPublisher in project helidon by oracle.

the class SubscriberInputStreamTest method testMultiple.

@Test
public void testMultiple() throws IOException {
    String oneValue = "someBytes";
    SubmissionPublisher<ByteBuffer> publisher = new SubmissionPublisher<>();
    SubscriberInputStream is = new SubscriberInputStream();
    publisher.subscribe(is);
    // asynchronously publish
    new Thread(() -> {
        for (int i = 0; i < 10; i++) {
            publisher.submit(ByteBuffer.wrap(oneValue.getBytes(StandardCharsets.UTF_8)));
        }
        publisher.close();
    }).start();
    byte[] buffer = new byte[16];
    int len;
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    while ((len = is.read(buffer)) != -1) {
        baos.write(buffer, 0, len);
    }
    String result = new String(baos.toByteArray(), StandardCharsets.UTF_8);
    StringBuilder expectedResult = new StringBuilder();
    for (int i = 0; i < 10; i++) {
        expectedResult.append(oneValue);
    }
    assertThat(result, is(expectedResult.toString()));
}