@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 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 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
}