@Test
public void demonstrateBroadcast() {
final Sink<Author, CompletionStage<Done>> writeAuthors = Sink.ignore();
final Sink<Hashtag, CompletionStage<Done>> writeHashtags = Sink.ignore();
// #flow-graph-broadcast
RunnableGraph.fromGraph(
GraphDSL.create(
b -> {
final UniformFanOutShape<Tweet, Tweet> bcast = b.add(Broadcast.create(2));
final FlowShape<Tweet, Author> toAuthor =
b.add(Flow.of(Tweet.class).map(t -> t.author));
final FlowShape<Tweet, Hashtag> toTags =
b.add(
Flow.of(Tweet.class)
.mapConcat(t -> new ArrayList<Hashtag>(t.hashtags())));
final SinkShape<Author> authors = b.add(writeAuthors);
final SinkShape<Hashtag> hashtags = b.add(writeHashtags);
b.from(b.add(tweets)).viaFanOut(bcast).via(toAuthor).to(authors);
b.from(bcast).via(toTags).to(hashtags);
return ClosedShape.getInstance();
}))
.run(mat);
// #flow-graph-broadcast
}
@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
}
@Test
public void partialGraph() throws Exception {
// #partial-graph
final Graph<FlowShape<Integer, Integer>, NotUsed> partial =
GraphDSL.create(
builder -> {
final UniformFanOutShape<Integer, Integer> B = builder.add(Broadcast.create(2));
final UniformFanInShape<Integer, Integer> C = builder.add(Merge.create(2));
final UniformFanOutShape<Integer, Integer> E = builder.add(Balance.create(2));
final UniformFanInShape<Integer, Integer> F = builder.add(Merge.create(2));
builder.from(F.out()).toInlet(C.in(0));
builder.from(B).viaFanIn(C).toFanIn(F);
builder
.from(B)
.via(builder.add(Flow.of(Integer.class).map(i -> i + 1)))
.viaFanOut(E)
.toFanIn(F);
return new FlowShape<Integer, Integer>(B.in(), E.out(1));
});
// #partial-graph
// #partial-use
Source.single(0).via(partial).to(Sink.ignore());
// #partial-use
// #partial-flow-dsl
// Convert the partial graph of FlowShape to a Flow to get
// access to the fluid DSL (for example to be able to call .filter())
final Flow<Integer, Integer, NotUsed> flow = Flow.fromGraph(partial);
// Simple way to create a graph backed Source
final Source<Integer, NotUsed> source =
Source.fromGraph(
GraphDSL.create(
builder -> {
final UniformFanInShape<Integer, Integer> merge = builder.add(Merge.create(2));
builder.from(builder.add(Source.single(0))).toFanIn(merge);
builder.from(builder.add(Source.from(Arrays.asList(2, 3, 4)))).toFanIn(merge);
// Exposing exactly one output port
return new SourceShape<Integer>(merge.out());
}));
// Building a Sink with a nested Flow, using the fluid DSL
final Sink<Integer, NotUsed> sink =
Flow.of(Integer.class).map(i -> i * 2).drop(10).named("nestedFlow").to(Sink.head());
// Putting all together
final RunnableGraph<NotUsed> closed = source.via(flow.filter(i -> i > 1)).to(sink);
// #partial-flow-dsl
}
@Test
public void complexGraph() throws Exception {
// #complex-graph
RunnableGraph.fromGraph(
GraphDSL.create(
builder -> {
final Outlet<Integer> A = builder.add(Source.single(0)).out();
final UniformFanOutShape<Integer, Integer> B = builder.add(Broadcast.create(2));
final UniformFanInShape<Integer, Integer> C = builder.add(Merge.create(2));
final FlowShape<Integer, Integer> D =
builder.add(Flow.of(Integer.class).map(i -> i + 1));
final UniformFanOutShape<Integer, Integer> E = builder.add(Balance.create(2));
final UniformFanInShape<Integer, Integer> F = builder.add(Merge.create(2));
final Inlet<Integer> G = builder.add(Sink.<Integer>foreach(System.out::println)).in();
builder.from(F).toFanIn(C);
builder.from(A).viaFanOut(B).viaFanIn(C).toFanIn(F);
builder.from(B).via(D).viaFanOut(E).toFanIn(F);
builder.from(E).toInlet(G);
return ClosedShape.getInstance();
}));
// #complex-graph
// #complex-graph-alt
RunnableGraph.fromGraph(
GraphDSL.create(
builder -> {
final SourceShape<Integer> A = builder.add(Source.single(0));
final UniformFanOutShape<Integer, Integer> B = builder.add(Broadcast.create(2));
final UniformFanInShape<Integer, Integer> C = builder.add(Merge.create(2));
final FlowShape<Integer, Integer> D =
builder.add(Flow.of(Integer.class).map(i -> i + 1));
final UniformFanOutShape<Integer, Integer> E = builder.add(Balance.create(2));
final UniformFanInShape<Integer, Integer> F = builder.add(Merge.create(2));
final SinkShape<Integer> G = builder.add(Sink.foreach(System.out::println));
builder.from(F.out()).toInlet(C.in(0));
builder.from(A).toInlet(B.in());
builder.from(B.out(0)).toInlet(C.in(1));
builder.from(C.out()).toInlet(F.in(0));
builder.from(B.out(1)).via(D).toInlet(E.in());
builder.from(E.out(0)).toInlet(F.in(1));
builder.from(E.out(1)).to(G);
return ClosedShape.getInstance();
}));
// #complex-graph-alt
}
@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 demonstrateASimplerOneToManyStage() throws Exception {
// tests:
Graph<FlowShape<Integer, Integer>, NotUsed> duplicator =
Flow.fromGraph(new Duplicator2<Integer>());
CompletionStage<Integer> result =
Source.from(Arrays.asList(1, 2, 3)).via(duplicator).runFold(0, (n, sum) -> n + sum, mat);
assertEquals(new Integer(12), result.toCompletableFuture().get(3, TimeUnit.SECONDS));
}
@Test
public void mustBeAbleToUseQueue() throws Exception {
final Pair<SourceQueueWithComplete<String>, CompletionStage<List<String>>> x =
Flow.of(String.class)
.runWith(Source.queue(2, OverflowStrategy.fail()), Sink.seq(), materializer);
final SourceQueueWithComplete<String> source = x.first();
final CompletionStage<List<String>> result = x.second();
source.offer("hello");
source.offer("world");
source.complete();
assertEquals(
result.toCompletableFuture().get(3, TimeUnit.SECONDS), Arrays.asList("hello", "world"));
}
@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
}
@Test
public void demonstrateAManyToOneElementGraphStage() throws Exception {
// tests:
Graph<FlowShape<Integer, Integer>, NotUsed> evenFilter =
Flow.fromGraph(new Filter<Integer>(n -> n % 2 == 0));
CompletionStage<Integer> result =
Source.from(Arrays.asList(1, 2, 3, 4, 5, 6))
.via(evenFilter)
.runFold(0, (elem, sum) -> sum + elem, mat);
assertEquals(new Integer(12), result.toCompletableFuture().get(3, TimeUnit.SECONDS));
}
@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
}
// #worker-pool
public static <In, Out> Flow<In, Out, BoxedUnit> balancer(
Flow<In, Out, BoxedUnit> worker, int workerCount) {
return Flow.fromGraph(
GraphDSL.create(
b -> {
boolean waitForAllDownstreams = true;
final UniformFanOutShape<In, In> balance =
b.add(Balance.<In>create(workerCount, waitForAllDownstreams));
final UniformFanInShape<Out, Out> merge = b.add(Merge.<Out>create(workerCount));
for (int i = 0; i < workerCount; i++) {
b.from(balance.out(i)).via(b.add(worker)).toInlet(merge.in(i));
}
return FlowShape.of(balance.in(), merge.out());
}));
}
@Test
public void demonstrateOneToOne() throws Exception {
// tests:
final Graph<FlowShape<String, Integer>, NotUsed> stringLength =
Flow.fromGraph(
new Map<String, Integer>(
new Function<String, Integer>() {
@Override
public Integer apply(String str) {
return str.length();
}
}));
CompletionStage<Integer> result =
Source.from(Arrays.asList("one", "two", "three"))
.via(stringLength)
.runFold(0, (sum, n) -> sum + n, mat);
assertEquals(new Integer(11), result.toCompletableFuture().get(3, TimeUnit.SECONDS));
}
@Test
public void mustBeAbleToUseConflate() throws Exception {
final JavaTestKit probe = new JavaTestKit(system);
final List<String> input = Arrays.asList("A", "B", "C");
CompletionStage<String> future =
Source.from(input)
.conflateWithSeed(s -> s, (aggr, in) -> aggr + in)
.runFold("", (aggr, in) -> aggr + in, materializer);
String result = future.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals("ABC", result);
final Flow<String, String, NotUsed> flow2 = Flow.of(String.class).conflate((a, b) -> a + b);
CompletionStage<String> future2 =
Source.from(input)
.conflate((String a, String b) -> a + b)
.runFold("", (a, b) -> a + b, materializer);
String result2 = future2.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals("ABC", result2);
}
@Test
public void mustWorksForTwoStreams() throws Exception {
final Flow<Integer, Integer, NotUsed> sharedThrottle =
Flow.of(Integer.class)
.throttle(1, FiniteDuration.create(1, TimeUnit.DAYS), 1, ThrottleMode.enforcing());
CompletionStage<List<Integer>> result1 =
Source.single(1).via(sharedThrottle).via(sharedThrottle).runWith(Sink.seq(), materializer);
// If there is accidental shared state then we would not be able to pass through the single
// element
assertEquals(
result1.toCompletableFuture().get(3, TimeUnit.SECONDS), Collections.singletonList(1));
// It works with a new stream, too
CompletionStage<List<Integer>> result2 =
Source.single(1).via(sharedThrottle).via(sharedThrottle).runWith(Sink.seq(), materializer);
assertEquals(
result2.toCompletableFuture().get(3, TimeUnit.SECONDS), Collections.singletonList(1));
}
@Test
public void demonstrateAnAsynchronousSideChannel() throws Exception {
// tests:
CompletableFuture<Done> switchF = new CompletableFuture<>();
Graph<FlowShape<Integer, Integer>, NotUsed> killSwitch =
Flow.fromGraph(new KillSwitch<>(switchF));
ExecutionContext ec = system.dispatcher();
CompletionStage<Integer> valueAfterKill = switchF.thenApply(in -> 4);
CompletionStage<Integer> result =
Source.from(Arrays.asList(1, 2, 3))
.concat(Source.fromCompletionStage(valueAfterKill))
.via(killSwitch)
.runFold(0, (n, sum) -> n + sum, mat);
switchF.complete(Done.getInstance());
assertEquals(new Integer(6), result.toCompletableFuture().get(3, TimeUnit.SECONDS));
}
public static void main(String[] args) {
Outlet<Integer> outlet = null;
Outlet<Integer> outlet1 = null;
Outlet<Integer> outlet2 = null;
Inlet<Integer> inlet = null;
Inlet<Integer> inlet1 = null;
Inlet<Integer> inlet2 = null;
Flow<Integer, Integer, BoxedUnit> flow = Flow.of(Integer.class);
Flow<Integer, Integer, BoxedUnit> flow1 = Flow.of(Integer.class);
Flow<Integer, Integer, BoxedUnit> flow2 = Flow.of(Integer.class);
Promise<Option<Integer>> promise = null;
{
Graph<SourceShape<Integer>, BoxedUnit> graphSource = null;
Graph<SinkShape<Integer>, BoxedUnit> graphSink = null;
Graph<FlowShape<Integer, Integer>, BoxedUnit> graphFlow = null;
// #flow-wrap
Source<Integer, BoxedUnit> source = Source.fromGraph(graphSource);
Sink<Integer, BoxedUnit> sink = Sink.fromGraph(graphSink);
Flow<Integer, Integer, BoxedUnit> aflow = Flow.fromGraph(graphFlow);
Flow.fromSinkAndSource(Sink.<Integer>head(), Source.single(0));
Flow.fromSinkAndSourceMat(Sink.<Integer>head(), Source.single(0), Keep.left());
// #flow-wrap
Graph<BidiShape<Integer, Integer, Integer, Integer>, BoxedUnit> bidiGraph = null;
// #bidi-wrap
BidiFlow<Integer, Integer, Integer, Integer, BoxedUnit> bidiFlow =
BidiFlow.fromGraph(bidiGraph);
BidiFlow.fromFlows(flow1, flow2);
BidiFlow.fromFlowsMat(flow1, flow2, Keep.both());
// #bidi-wrap
}
{
// #graph-create
GraphDSL.create(
builder -> {
// ...
return ClosedShape.getInstance();
});
GraphDSL.create(
builder -> {
// ...
return new FlowShape<>(inlet, outlet);
});
// #graph-create
}
{
// #graph-create-2
GraphDSL.create(
builder -> {
// ...
return SourceShape.of(outlet);
});
GraphDSL.create(
builder -> {
// ...
return SinkShape.of(inlet);
});
GraphDSL.create(
builder -> {
// ...
return FlowShape.of(inlet, outlet);
});
GraphDSL.create(
builder -> {
// ...
return BidiShape.of(inlet1, outlet1, inlet2, outlet2);
});
// #graph-create-2
}
{
// #graph-builder
GraphDSL.create(
builder -> {
builder.from(outlet).toInlet(inlet);
builder.from(outlet).via(builder.add(flow)).toInlet(inlet);
builder.from(builder.add(Source.single(0))).to(builder.add(Sink.head()));
// ...
return ClosedShape.getInstance();
});
// #graph-builder
}
// #source-creators
Source<Integer, Promise<Option<Integer>>> src = Source.<Integer>maybe();
// Complete the promise with an empty option to emulate the old lazyEmpty
promise.trySuccess(scala.Option.empty());
final Source<String, Cancellable> ticks =
Source.tick(
FiniteDuration.create(0, TimeUnit.MILLISECONDS),
FiniteDuration.create(200, TimeUnit.MILLISECONDS),
"tick");
final Source<Integer, BoxedUnit> pubSource =
Source.fromPublisher(TestPublisher.<Integer>manualProbe(true, sys));
final Source<Integer, BoxedUnit> futSource = Source.fromFuture(Futures.successful(42));
final Source<Integer, Subscriber<Integer>> subSource = Source.<Integer>asSubscriber();
// #source-creators
// #sink-creators
final Sink<Integer, BoxedUnit> subSink =
Sink.fromSubscriber(TestSubscriber.<Integer>manualProbe(sys));
// #sink-creators
// #sink-as-publisher
final Sink<Integer, Publisher<Integer>> pubSink = Sink.<Integer>asPublisher(false);
final Sink<Integer, Publisher<Integer>> pubSinkFanout = Sink.<Integer>asPublisher(true);
// #sink-as-publisher
// #empty-flow
Flow<Integer, Integer, BoxedUnit> emptyFlow = Flow.<Integer>create();
// or
Flow<Integer, Integer, BoxedUnit> emptyFlow2 = Flow.of(Integer.class);
// #empty-flow
// #flatMapConcat
Flow.<Source<Integer, BoxedUnit>>create()
.<Integer, BoxedUnit>flatMapConcat(
new Function<Source<Integer, BoxedUnit>, Source<Integer, BoxedUnit>>() {
@Override
public Source<Integer, BoxedUnit> apply(Source<Integer, BoxedUnit> param)
throws Exception {
return param;
}
});
// #flatMapConcat
Uri uri = null;
// #raw-query
final akka.japi.Option<String> theRawQueryString = uri.rawQueryString();
// #raw-query
// #query-param
final akka.japi.Option<String> aQueryParam = uri.query().get("a");
// #query-param
// #file-source-sink
final Source<ByteString, Future<Long>> fileSrc = FileIO.fromFile(new File("."));
final Source<ByteString, Future<Long>> otherFileSrc = FileIO.fromFile(new File("."), 1024);
final Sink<ByteString, Future<Long>> fileSink = FileIO.toFile(new File("."));
// #file-source-sink
// #input-output-stream-source-sink
final Source<ByteString, Future<java.lang.Long>> inputStreamSrc =
StreamConverters.fromInputStream(
new Creator<InputStream>() {
public InputStream create() {
return new SomeInputStream();
}
});
final Source<ByteString, Future<java.lang.Long>> otherInputStreamSrc =
StreamConverters.fromInputStream(
new Creator<InputStream>() {
public InputStream create() {
return new SomeInputStream();
}
},
1024);
final Sink<ByteString, Future<java.lang.Long>> outputStreamSink =
StreamConverters.fromOutputStream(
new Creator<OutputStream>() {
public OutputStream create() {
return new SomeOutputStream();
}
});
// #input-output-stream-source-sink
// #output-input-stream-source-sink
final FiniteDuration timeout = FiniteDuration.Zero();
final Source<ByteString, OutputStream> outputStreamSrc = StreamConverters.asOutputStream();
final Source<ByteString, OutputStream> otherOutputStreamSrc =
StreamConverters.asOutputStream(timeout);
final Sink<ByteString, InputStream> someInputStreamSink = StreamConverters.asInputStream();
final Sink<ByteString, InputStream> someOtherInputStreamSink =
StreamConverters.asInputStream(timeout);
// #output-input-stream-source-sink
}