示例#1
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  @Test
  public void reusingComponents() throws Exception {
    final Source<Integer, NotUsed> nestedSource =
        Source.single(0) // An atomic source
            .map(i -> i + 1) // an atomic processing stage
            .named("nestedSource"); // wraps up the current Source and gives it a name

    final Flow<Integer, Integer, NotUsed> nestedFlow =
        Flow.of(Integer.class)
            .filter(i -> i != 0) // an atomic processing stage
            .map(i -> i - 2) // another atomic processing stage
            .named("nestedFlow"); // wraps up the Flow, and gives it a name

    final Sink<Integer, NotUsed> nestedSink =
        nestedFlow
            .to(Sink.fold(0, (acc, i) -> acc + i)) // wire an atomic sink to the nestedFlow
            .named("nestedSink"); // wrap it up

    // #reuse
    // Create a RunnableGraph from our components
    final RunnableGraph<NotUsed> runnableGraph = nestedSource.to(nestedSink);

    // Usage is uniform, no matter if modules are composite or atomic
    final RunnableGraph<NotUsed> runnableGraph2 =
        Source.single(0).to(Sink.fold(0, (acc, i) -> acc + i));
    // #reuse
  }
示例#2
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  @Test
  public void nonNestedFlow() throws Exception {
    // #non-nested-flow
    Source.single(0)
        .map(i -> i + 1)
        .filter(i -> i != 0)
        .map(i -> i - 2)
        .to(Sink.fold(0, (acc, i) -> acc + i));

    // ... where is the nesting?
    // #non-nested-flow
  }
示例#3
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  @Test
  public void demonstrateChainingOfGraphStages() throws Exception {
    Graph<SinkShape<Integer>, CompletionStage<String>> sink =
        Sink.fold("", (acc, n) -> acc + n.toString());

    // #graph-stage-chain
    CompletionStage<String> resultFuture =
        Source.from(Arrays.asList(1, 2, 3, 4, 5))
            .via(new Filter<Integer>((n) -> n % 2 == 0))
            .via(new Duplicator<Integer>())
            .via(new Map<Integer, Integer>((n) -> n / 2))
            .runWith(sink, mat);

    // #graph-stage-chain

    assertEquals("1122", resultFuture.toCompletableFuture().get(3, TimeUnit.SECONDS));
  }
示例#4
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  @Test
  public void materializedValues() throws Exception {
    // #mat-combine-1
    // Materializes to Promise<BoxedUnit>                                     (red)
    final Source<Integer, CompletableFuture<Optional<Integer>>> source = Source.<Integer>maybe();

    // Materializes to BoxedUnit                                              (black)
    final Flow<Integer, Integer, NotUsed> flow1 = Flow.of(Integer.class).take(100);

    // Materializes to Promise<Option<>>                                     (red)
    final Source<Integer, CompletableFuture<Optional<Integer>>> nestedSource =
        source.viaMat(flow1, Keep.left()).named("nestedSource");
    // #mat-combine-1

    // #mat-combine-2
    // Materializes to BoxedUnit                                              (orange)
    final Flow<Integer, ByteString, NotUsed> flow2 =
        Flow.of(Integer.class).map(i -> ByteString.fromString(i.toString()));

    // Materializes to Future<OutgoingConnection>                             (yellow)
    final Flow<ByteString, ByteString, CompletionStage<OutgoingConnection>> flow3 =
        Tcp.get(system).outgoingConnection("localhost", 8080);

    // Materializes to Future<OutgoingConnection>                             (yellow)
    final Flow<Integer, ByteString, CompletionStage<OutgoingConnection>> nestedFlow =
        flow2.viaMat(flow3, Keep.right()).named("nestedFlow");
    // #mat-combine-2

    // #mat-combine-3
    // Materializes to Future<String>                                         (green)
    final Sink<ByteString, CompletionStage<String>> sink =
        Sink.<String, ByteString>fold("", (acc, i) -> acc + i.utf8String());

    // Materializes to Pair<Future<OutgoingConnection>, Future<String>>       (blue)
    final Sink<Integer, Pair<CompletionStage<OutgoingConnection>, CompletionStage<String>>>
        nestedSink = nestedFlow.toMat(sink, Keep.both());
    // #mat-combine-3

    // #mat-combine-4b
    // Materializes to Future<MyClass>                                        (purple)
    final RunnableGraph<CompletionStage<MyClass>> runnableGraph =
        nestedSource.toMat(nestedSink, Combiner::f);
    // #mat-combine-4b
  }
  @Test
  public void demonstrateMaterializeMultipleTimes() {
    final Source<Tweet, NotUsed> tweetsInMinuteFromNow =
        tweets; // not really in second, just acting as if

    // #tweets-runnable-flow-materialized-twice
    final Sink<Integer, CompletionStage<Integer>> sumSink =
        Sink.<Integer, Integer>fold(0, (acc, elem) -> acc + elem);
    final RunnableGraph<CompletionStage<Integer>> counterRunnableGraph =
        tweetsInMinuteFromNow
            .filter(t -> t.hashtags().contains(AKKA))
            .map(t -> 1)
            .toMat(sumSink, Keep.right());

    // materialize the stream once in the morning
    final CompletionStage<Integer> morningTweetsCount = counterRunnableGraph.run(mat);
    // and once in the evening, reusing the blueprint
    final CompletionStage<Integer> eveningTweetsCount = counterRunnableGraph.run(mat);
    // #tweets-runnable-flow-materialized-twice

  }
  @Test
  public void demonstrateCountOnFiniteStream() {
    // #tweets-fold-count
    final Sink<Integer, CompletionStage<Integer>> sumSink =
        Sink.<Integer, Integer>fold(0, (acc, elem) -> acc + elem);

    final RunnableGraph<CompletionStage<Integer>> counter =
        tweets.map(t -> 1).toMat(sumSink, Keep.right());

    final CompletionStage<Integer> sum = counter.run(mat);

    sum.thenAcceptAsync(
        c -> System.out.println("Total tweets processed: " + c), system.dispatcher());
    // #tweets-fold-count

    new Object() {
      // #tweets-fold-count-oneline
      final CompletionStage<Integer> sum = tweets.map(t -> 1).runWith(sumSink, mat);
      // #tweets-fold-count-oneline
    };
  }
示例#7
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  @Test
  public void attributes() throws Exception {
    // #attributes-inheritance
    final Source<Integer, NotUsed> nestedSource =
        Source.single(0).map(i -> i + 1).named("nestedSource"); // Wrap, no inputBuffer set

    final Flow<Integer, Integer, NotUsed> nestedFlow =
        Flow.of(Integer.class)
            .filter(i -> i != 0)
            .via(
                Flow.of(Integer.class)
                    .map(i -> i - 2)
                    .withAttributes(Attributes.inputBuffer(4, 4))) // override
            .named("nestedFlow"); // Wrap, no inputBuffer set

    final Sink<Integer, NotUsed> nestedSink =
        nestedFlow
            .to(Sink.fold(0, (acc, i) -> acc + i)) // wire an atomic sink to the nestedFlow
            .withAttributes(
                Attributes.name("nestedSink").and(Attributes.inputBuffer(3, 3))); // override
    // #attributes-inheritance
  }
示例#8
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  @Test
  public void nestedFlow() throws Exception {
    // #nested-flow
    final Source<Integer, NotUsed> nestedSource =
        Source.single(0) // An atomic source
            .map(i -> i + 1) // an atomic processing stage
            .named("nestedSource"); // wraps up the current Source and gives it a name

    final Flow<Integer, Integer, NotUsed> nestedFlow =
        Flow.of(Integer.class)
            .filter(i -> i != 0) // an atomic processing stage
            .map(i -> i - 2) // another atomic processing stage
            .named("nestedFlow"); // wraps up the Flow, and gives it a name

    final Sink<Integer, NotUsed> nestedSink =
        nestedFlow
            .to(Sink.fold(0, (acc, i) -> acc + i)) // wire an atomic sink to the nestedFlow
            .named("nestedSink"); // wrap it up

    // Create a RunnableGraph
    final RunnableGraph<NotUsed> runnableGraph = nestedSource.to(nestedSink);
    // #nested-flow
  }