@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 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
}
@Test
public void closedGraph() throws Exception {
// #embed-closed
final RunnableGraph<NotUsed> closed1 = Source.single(0).to(Sink.foreach(System.out::println));
final RunnableGraph<NotUsed> closed2 =
RunnableGraph.fromGraph(
GraphDSL.create(
builder -> {
final ClosedShape embeddedClosed = builder.add(closed1);
return embeddedClosed; // Could return ClosedShape.getInstance()
}));
// #embed-closed
}
@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 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 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
}