Java Code Examples for org.reactivestreams.Publisher#subscribe()

@Override
public void onNext(T t) {
	long idx = INDEX.incrementAndGet(this);

	if (!Operators.set(OTHER, this, Operators.emptySubscription())) {
		return;
	}

	Publisher<U> p;

	try {
		p = Objects.requireNonNull(throttler.apply(t),
				"throttler returned a null publisher");
	}
	catch (Throwable e) {
		onError(Operators.onOperatorError(s, e, t, ctx));
		return;
	}

	SampleTimeoutOther<T, U> os = new SampleTimeoutOther<>(this, t, idx);

	if (Operators.replace(OTHER, this, os)) {
		p.subscribe(os);
	}
}
 

@Test
public void testBuildingSubscriberFromSpec() throws ExecutionException, InterruptedException {
    Processor<ByteBuffer, MyDomainObject> parser = createParser();

    CompletionSubscriber<ByteBuffer, List<MyDomainObject>> subscriber = ReactiveStreams.<ByteBuffer> builder()
            .via(parser)
            .toList()
            .build();

    CompletionStage<List<MyDomainObject>> result = subscriber.getCompletion();

    List<MyDomainObject> domainObjects = Arrays.asList(new MyDomainObject("Clement", "Neo"),
            new MyDomainObject("Tintin", "Milou"));
    Publisher<ByteBuffer> publisher = ReactiveStreams.fromIterable(domainObjects)
            .map(obj -> String.format("%s,%s\n", obj.field1, obj.field2))
            .map(line -> ByteBuffer.wrap(line.getBytes()))
            .buildRs();

    publisher.subscribe(subscriber);
    List<MyDomainObject> objects = result.toCompletableFuture().get();
    assertThat(objects.toString()).contains("Clement => Neo", "Tintin => Milou");
}
 

void subscribe(Publisher<? extends T>[] sources,
		int n,
		CoreSubscriber<? super T> actual) {
	FirstEmittingSubscriber<T>[] a = subscribers;

	for (int i = 0; i < n; i++) {
		a[i] = new FirstEmittingSubscriber<>(actual, this, i);
	}

	actual.onSubscribe(this);

	for (int i = 0; i < n; i++) {
		if (cancelled || wip != Integer.MIN_VALUE) {
			return;
		}

		Publisher<? extends T> p = sources[i];

		if (p == null) {
			if (WIP.compareAndSet(this, Integer.MIN_VALUE, -1)) {
				actual.onError(new NullPointerException("The " + i + " th Publisher source is null"));
			}
			return;
		}

		p.subscribe(a[i]);
	}

}
 

@Override
public void onNext(T t) {
	if (!gate) {
		gate = true;

		if (wip == 0 && WIP.compareAndSet(this, 0, 1)) {
			actual.onNext(t);
			if (WIP.decrementAndGet(this) != 0) {
				handleTermination();
				return;
			}
		}
		else {
			return;
		}

		Publisher<U> p;

		try {
			p = Objects.requireNonNull(throttler.apply(t),
					"The throttler returned a null publisher");
		}
		catch (Throwable e) {
			Operators.terminate(S, this);
			error(Operators.onOperatorError(null, e, t, ctx));
			return;
		}

		SampleFirstOther<U> other = new SampleFirstOther<>(this);

		if (Operators.replace(OTHER, this, other)) {
			p.subscribe(other);
		}
	}
	else {
		Operators.onDiscard(t, ctx);
	}
}
 

protected boolean isStreamingSubscriberUsed(Publisher<?> publisher,
                                            AsyncResponse asyncResponse, 
                                            Message inMessage) {
    if (isUseStreamingSubscriberIfPossible() && isJsonResponse(inMessage)) {
        publisher.subscribe(new JsonStreamingAsyncSubscriber<>(asyncResponse));
        return true;
    } else {
        return false;
    }
}
 

public void onNext(T t) {
    if (!running)
        return;
    try {
        Publisher<? extends R> next = mapper.apply(t);
        ActiveSubscriber inner = new ActiveSubscriber();
        queueUpdater.getAndUpdate(this, q -> q.plus(inner));
        next.subscribe(inner);
    }catch(Throwable e){
        onError.accept(e);
    }

}
 

@Override
public void onComplete() {
    // read of the first should occur before the read of inner since otherwise
    // first may be nulled while the previous read has shown that inner is still
    // null hence double invocation of transformer occurs
    final T f = this.first;
    final CoreSubscriber<? super T> i = this.inner;
    if (this.done || i == Operators.EMPTY_SUBSCRIBER) {
        return;
    }

    this.done = true;

    if (f == null && i == null) {
        final Publisher<? extends R> result;
        final CoreSubscriber<? super R> o = outer;

        try {
            result = Objects.requireNonNull(
                    this.transformer.apply(Signal.complete(o.currentContext()), this),
                "The transformer returned a null value"
            );
        }
        catch (Throwable e) {
            this.done = true;
            Operators.error(o, Operators.onOperatorError(this.s, e, null, o.currentContext()));
            return;
        }

        result.subscribe(o);
        return;
    }

    drain();
}
 

@Benchmark
public void createNew(Blackhole bh) {
    Publisher<Integer> p = new PublisherRange(0, count);
    bh.consume(p);
    p.subscribe(new PerfSubscriber(bh));
}
 

@Test
public void ensureNoLeaksPopulatedQueueAndRacingCancelAndOnError() {
	Assumptions.assumeThat(discardScenario.subscriptionsNumber).isOne();
	for (int i = 0; i < 10000; i++) {
		tracker.reset();
		TestPublisher<Tracked> testPublisher = TestPublisher.createNoncompliant(
				TestPublisher.Violation.DEFER_CANCELLATION,
				TestPublisher.Violation.REQUEST_OVERFLOW);
		@SuppressWarnings("unchecked")
		Publisher<Tracked> source = discardScenario.producePublisherFromSources(testPublisher);

		if (conditional) {
			if (source instanceof Flux) {
				source = ((Flux<Tracked>) source).filter(t -> true);
			}
			else {
				source = ((Mono<Tracked>) source).filter(t -> true);
			}
		}

		Scannable scannable = Scannable.from(source);
		Integer prefetch = scannable.scan(Scannable.Attr.PREFETCH);

		Assumptions.assumeThat(prefetch).isNotZero();

		AssertSubscriber<Tracked> assertSubscriber = new AssertSubscriber<>(Operators.enableOnDiscard(null, Tracked::safeRelease), 0);
		if (fused) {
			assertSubscriber.requestedFusionMode(Fuseable.ANY);
		}
		source.subscribe(assertSubscriber);

		testPublisher.next(tracker.track(1));
		testPublisher.next(tracker.track(2));
		testPublisher.next(tracker.track(3));
		testPublisher.next(tracker.track(4));

		RaceTestUtils.race(
				assertSubscriber::cancel,
				() -> testPublisher.error(new RuntimeException("test")),
				scheduler);

		List<Tracked> values = assertSubscriber.values();
		values.forEach(Tracked::release);
		if (assertSubscriber.isTerminated()) {
			// has a chance to error with rejected exception
			assertSubscriber.assertError();
		}

		tracker.assertNoLeaks();
	}
}
 

@Benchmark
public void createNew(Blackhole bh) {
    Publisher<Integer> p = createSource();
    bh.consume(p);
    p.subscribe(new PerfSubscriber(bh));
}
 

@Override
public void onCompletion() {
    if (wip.getAndIncrement() == 0) {
        Publisher<? extends T>[] a = upstreams;
        do {

            if (isCancelled()) {
                return;
            }

            int i = index;
            if (i == a.length) {
                Throwable last = Subscriptions.markFailureAsTerminated(failure);
                if (last != null) {
                    downstream.onFailure(last);
                } else {
                    downstream.onCompletion();
                }
                return;
            }

            Publisher<? extends T> p = a[i];

            if (p == null) {
                downstream.onFailure(
                        new NullPointerException("Source Publisher at currentIndex " + i + " is null"));
                return;
            }

            long c = produced;
            if (c != 0L) {
                produced = 0L;
                emitted(c);
            }
            p.subscribe(Infrastructure.onMultiSubscription(p, this));

            if (isCancelled()) {
                return;
            }

            index = ++i;
        } while (wip.decrementAndGet() != 0);
    }

}
 

@Benchmark
public void createNew2(Blackhole bh) {
    Publisher<Integer> p = createSource2();
    bh.consume(p);
    p.subscribe(new PerfSubscriber(bh));
}
 

@Test
public void ensureNoLeaksPopulatedQueueAndRacingCancelAndOnNext() {
	Assumptions.assumeThat(discardScenario.subscriptionsNumber).isOne();
	for (int i = 0; i < 10000; i++) {
		tracker.reset();
		TestPublisher<Tracked> testPublisher = TestPublisher.createNoncompliant(
				TestPublisher.Violation.DEFER_CANCELLATION,
				TestPublisher.Violation.REQUEST_OVERFLOW);
		Publisher<Tracked> source = discardScenario.producePublisherFromSources(testPublisher);

		if (conditional) {
			if (source instanceof Flux) {
				source = ((Flux<Tracked>) source).filter(t -> true);
			}
			else {
				source = ((Mono<Tracked>) source).filter(t -> true);
			}
		}

		Scannable scannable = Scannable.from(source);
		Integer prefetch = scannable.scan(Scannable.Attr.PREFETCH);

		Assumptions.assumeThat(prefetch).isNotZero();

		AssertSubscriber<Tracked> assertSubscriber = new AssertSubscriber<>(Operators.enableOnDiscard(null, Tracked::safeRelease), 0);
		if (fused) {
			assertSubscriber.requestedFusionMode(Fuseable.ANY);
		}
		source.subscribe(assertSubscriber);

		testPublisher.next(tracker.track(1));
		testPublisher.next(tracker.track(2));

		Tracked value3 = tracker.track(3);
		Tracked value4 = tracker.track(4);
		Tracked value5 = tracker.track(5);

		RaceTestUtils.race(assertSubscriber::cancel, () -> {
			testPublisher.next(value3);
			testPublisher.next(value4);
			testPublisher.next(value5);
		}, scheduler);

		List<Tracked> values = assertSubscriber.values();
		values.forEach(Tracked::release);

		tracker.assertNoLeaks();
	}
}
 

@Override
public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
	body.subscribe(this.writeSubscriber);
	return Mono.never();
}
 

@ParameterizedTest
@MethodSource("requestNInteractions")
public void ensuresThatNoOpsMustHappenUntilFirstRequestN(
    FrameType frameType, BiFunction<ClientSocketRule, Payload, Publisher<Payload>> interaction) {
  Payload payload1 = ByteBufPayload.create("abc1");
  Publisher<Payload> interaction1 = interaction.apply(rule, payload1);

  Payload payload2 = ByteBufPayload.create("abc2");
  Publisher<Payload> interaction2 = interaction.apply(rule, payload2);

  Assertions.assertThat(rule.connection.getSent()).isEmpty();

  AssertSubscriber<Payload> assertSubscriber1 = AssertSubscriber.create(0);
  interaction1.subscribe(assertSubscriber1);
  AssertSubscriber<Payload> assertSubscriber2 = AssertSubscriber.create(0);
  interaction2.subscribe(assertSubscriber2);
  assertSubscriber1.assertNotTerminated().assertNoError();
  assertSubscriber2.assertNotTerminated().assertNoError();
  // even though we subscribed, nothing should happen until the first requestN
  Assertions.assertThat(rule.connection.getSent()).isEmpty();

  // first request on the second interaction to ensure that stream id issuing on the first request
  assertSubscriber2.request(1);

  Assertions.assertThat(rule.connection.getSent())
      .hasSize(1)
      .first()
      .matches(bb -> frameType(bb) == frameType)
      .matches(
          bb -> FrameHeaderCodec.streamId(bb) == 1,
          "Expected to have stream ID {1} but got {"
              + FrameHeaderCodec.streamId(rule.connection.getSent().iterator().next())
              + "}")
      .matches(
          bb -> {
            switch (frameType) {
              case REQUEST_RESPONSE:
                return ByteBufUtil.equals(
                    RequestResponseFrameCodec.data(bb),
                    Unpooled.wrappedBuffer("abc2".getBytes()));
              case REQUEST_STREAM:
                return ByteBufUtil.equals(
                    RequestStreamFrameCodec.data(bb), Unpooled.wrappedBuffer("abc2".getBytes()));
              case REQUEST_CHANNEL:
                return ByteBufUtil.equals(
                    RequestChannelFrameCodec.data(bb), Unpooled.wrappedBuffer("abc2".getBytes()));
            }

            return false;
          })
      .matches(ReferenceCounted::release);

  rule.connection.clearSendReceiveBuffers();

  assertSubscriber1.request(1);
  Assertions.assertThat(rule.connection.getSent())
      .hasSize(1)
      .first()
      .matches(bb -> frameType(bb) == frameType)
      .matches(
          bb -> FrameHeaderCodec.streamId(bb) == 3,
          "Expected to have stream ID {1} but got {"
              + FrameHeaderCodec.streamId(rule.connection.getSent().iterator().next())
              + "}")
      .matches(
          bb -> {
            switch (frameType) {
              case REQUEST_RESPONSE:
                return ByteBufUtil.equals(
                    RequestResponseFrameCodec.data(bb),
                    Unpooled.wrappedBuffer("abc1".getBytes()));
              case REQUEST_STREAM:
                return ByteBufUtil.equals(
                    RequestStreamFrameCodec.data(bb), Unpooled.wrappedBuffer("abc1".getBytes()));
              case REQUEST_CHANNEL:
                return ByteBufUtil.equals(
                    RequestChannelFrameCodec.data(bb), Unpooled.wrappedBuffer("abc1".getBytes()));
            }

            return false;
          })
      .matches(ReferenceCounted::release);
}
 

@ParameterizedTest
@MethodSource("encodeDecodePayloadCases")
public void verifiesThatFrameWithNoMetadataHasDecodedCorrectlyIntoPayload(
    FrameType frameType, int framesCnt, int responsesCnt) {
  ByteBufAllocator allocator = rule.alloc();
  AssertSubscriber<Payload> assertSubscriber = AssertSubscriber.create(responsesCnt);
  TestPublisher<Payload> testPublisher = TestPublisher.create();

  Publisher<Payload> response;

  switch (frameType) {
    case REQUEST_FNF:
      response =
          testPublisher.mono().flatMap(p -> rule.socket.fireAndForget(p).then(Mono.empty()));
      break;
    case REQUEST_RESPONSE:
      response = testPublisher.mono().flatMap(p -> rule.socket.requestResponse(p));
      break;
    case REQUEST_STREAM:
      response = testPublisher.mono().flatMapMany(p -> rule.socket.requestStream(p));
      break;
    case REQUEST_CHANNEL:
      response = rule.socket.requestChannel(testPublisher.flux());
      break;
    default:
      throw new UnsupportedOperationException("illegal case");
  }

  response.subscribe(assertSubscriber);
  testPublisher.next(ByteBufPayload.create("d"));

  int streamId = rule.getStreamIdForRequestType(frameType);

  if (responsesCnt > 0) {
    for (int i = 0; i < responsesCnt - 1; i++) {
      rule.connection.addToReceivedBuffer(
          PayloadFrameCodec.encode(
              allocator,
              streamId,
              false,
              false,
              true,
              null,
              Unpooled.wrappedBuffer(("rd" + (i + 1)).getBytes())));
    }

    rule.connection.addToReceivedBuffer(
        PayloadFrameCodec.encode(
            allocator,
            streamId,
            false,
            true,
            true,
            null,
            Unpooled.wrappedBuffer(("rd" + responsesCnt).getBytes())));
  }

  if (framesCnt > 1) {
    rule.connection.addToReceivedBuffer(
        RequestNFrameCodec.encode(allocator, streamId, framesCnt));
  }

  for (int i = 1; i < framesCnt; i++) {
    testPublisher.next(ByteBufPayload.create("d" + i));
  }

  Assertions.assertThat(rule.connection.getSent())
      .describedAs(
          "Interaction Type :[%s]. Expected to observe %s frames sent", frameType, framesCnt)
      .hasSize(framesCnt)
      .allMatch(bb -> !FrameHeaderCodec.hasMetadata(bb))
      .allMatch(ByteBuf::release);

  Assertions.assertThat(assertSubscriber.isTerminated())
      .describedAs("Interaction Type :[%s]. Expected to be terminated", frameType)
      .isTrue();

  Assertions.assertThat(assertSubscriber.values())
      .describedAs(
          "Interaction Type :[%s]. Expected to observe %s frames received",
          frameType, responsesCnt)
      .hasSize(responsesCnt)
      .allMatch(p -> !p.hasMetadata())
      .allMatch(p -> p.release());

  rule.assertHasNoLeaks();
  rule.connection.clearSendReceiveBuffers();
}
 

@Override
public Removable addUpstream(Publisher publisher) {
    publisher.subscribe(new Subscriber() {

        Subscription s;

        @Override
        public void onSubscribe(final Subscription subscription) {
            s = subscription;
            subscriptions.put(publisher, s);
            s.request(cnt.get());
        }

        @Override
        public void onNext(Object o) {
            proc.onNext(o);
            cnt.decrementAndGet();
            if (cnt.compareAndSet(0, mat.settings().maxInputBufferSize())) {
                try {
                    //todo super hack:
                    // Akka internal subscriber request chunks of data
                    // it might happen that we call onNext where internal subscriber did not
                    // request the next chunk. this is why we wait a little and try to use the
                    // same ratio as internals
                    Thread.sleep(33);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                s.request(mat.settings().maxInputBufferSize());
            }
        }

        @Override
        public void onError(Throwable t) {
            if (tePolicy.equals(WRAP)) {
                proc.onNext(new Event.ErrorEvent(t));
                cnt.decrementAndGet();
                cnt.compareAndSet(0, mat.settings().maxInputBufferSize());
            } else if (tePolicy.equals(PASS)) {
                proc.onError(t);
            }
        }

        @Override
        public void onComplete() {
            if (tePolicy.equals(WRAP)) {
                proc.onNext(Event.COMPLETE);
                cnt.decrementAndGet();
                cnt.compareAndSet(0, mat.settings().maxInputBufferSize());
            } else if (tePolicy.equals(PASS)) {
                proc.onComplete();
            }
        }
    });
    return () -> removeUpstream(publisher);
}
 

@Override
public void write(final ChannelHandlerContext ctx, Object msg, final ChannelPromise promise) throws Exception {
    if (msg instanceof Publisher) {
        @SuppressWarnings("unchecked")
        final Publisher<W> data = (Publisher<W>) msg;

        data.subscribe(new Subscriber<W>() {

            // TODO: Needs to be fixed to wire all futures to the promise of the Publisher write.
            private ChannelFuture lastWriteFuture;

            @Override
            public void onSubscribe(Subscription s) {
                s.request(Long.MAX_VALUE); // TODO: Backpressure
            }

            @Override
            public void onNext(W w) {
                lastWriteFuture = ctx.channel().write(w);
            }

            @Override
            public void onError(Throwable t) {
                onTerminate();
            }

            @Override
            public void onComplete() {
                onTerminate();
            }

            private void onTerminate() {
                ctx.channel().flush();
                lastWriteFuture.addListener(new ChannelFutureListener() {
                    @Override
                    public void operationComplete(ChannelFuture future) throws Exception {
                        if (future.isSuccess()) {
                            promise.trySuccess();
                        } else {
                            promise.tryFailure(future.cause());
                        }
                    }
                });
            }
        });
    } else {
        super.write(ctx, msg, promise);
    }
}
 

@Override
public void onNext(T t) {
	Publisher<? extends R> publisher;

	try {
		publisher = Objects.requireNonNull(mapper.apply(t), "publisher");
	}
	catch (Throwable ex) {
		onError(Operators.onOperatorError(s, ex, t, actual.currentContext()));
		return;
	}

	MergeSequentialInner<R> inner = new MergeSequentialInner<>(this, prefetch);

	if (cancelled) {
		return;
	}

	if (!subscribers.offer(inner)) {
		int badSize = subscribers.size();
		inner.cancel();
		drainAndCancel();
		onError(Operators.onOperatorError(s,
				new IllegalStateException("Too many subscribers for " +
						"fluxMergeSequential on item: " + t +
						"; subscribers: " + badSize),
				t, actual.currentContext()));
		return;
	}

	if (cancelled) {
		return;
	}

	publisher.subscribe(inner);

	if (cancelled) {
		inner.cancel();
		drainAndCancel();
	}
}
 

@Test(expected = RuntimeException.class)
public void errorNotPropagatedWhenCancelHandlerThrows() throws IOException {
    // This is not a nice behavior, but test is to confirm root cause of issue seen live, where
    // a subscription dies and does not recover as we time out trying to stop the subscription
    // that we're currently handling an error for!
    String streamId = "test-stream";

    when(reader.readValue((byte[]) any())).thenReturn(new Object());
    // Subscribe call not yet mocked, ensures we don't call subscribe until we subscribe
    // to the Flux
    Publisher<EventSubscriptionUpdate<Event>> publisher = repository.getStreamPublisher(
            streamId,
            null);

    // Set up subscription - should trigger a call to underlying subscribe
    CatchUpSubscription catchUpSubscription = mock(CatchUpSubscription.class);
    when(eventStore.subscribeToStreamFrom(
            anyString(),
            any(Long.class),
            any(CatchUpSubscriptionSettings.class),
            any(CatchUpSubscriptionListener.class),
            any(UserCredentials.class)))
            .thenReturn(catchUpSubscription);

    // Hook up fake listener, checking that we're getting notified
    AtomicInteger seenEvents = new AtomicInteger(0);
    AtomicReference<Throwable> seenError = new AtomicReference<>(null);
    AtomicBoolean seenStop = new AtomicBoolean(false);
    publisher.subscribe(Subscribers.bounded(
            100,
            event -> seenEvents.incrementAndGet(),
            seenError::set,
            () -> seenStop.set(true)));

    ArgumentCaptor<CatchUpSubscriptionListener> listenerCaptor =
            ArgumentCaptor.forClass(CatchUpSubscriptionListener.class);

    verify(eventStore, times(1)).subscribeToStreamFrom(
            eq("pref-" + streamId),
            eq(null),
            any(CatchUpSubscriptionSettings.class),
            listenerCaptor.capture());

    CatchUpSubscriptionListener listener = listenerCaptor.getValue();
    Mockito
            .doThrow(new RuntimeException("bad stuff on close"))
            .when(catchUpSubscription).stop();
    listener.onClose(
            catchUpSubscription,
            SubscriptionDropReason.CatchUpError,
            new RuntimeException("bad things happen"));

    Assert.assertEquals(0, seenEvents.get());
    Assert.assertNull(seenError.get());
}