public void demonstrateAGraphStageWithATimer() throws Exception {
// tests:
CompletionStage<Integer> result =
Source.from(Arrays.asList(1, 2, 3))
.via(new TimedGate<>(Duration.create(2, "seconds")))
.takeWithin(Duration.create(250, "millis"))
.runFold(0, (n, sum) -> n + sum, mat);
assertEquals(new Integer(1), result.toCompletableFuture().get(3, TimeUnit.SECONDS));
}
public void demonstrateACustomMaterializedValue() throws Exception {
// tests:
RunnableGraph<CompletionStage<Integer>> flow =
Source.from(Arrays.asList(1, 2, 3))
.viaMat(new FirstValue(), Keep.right())
.to(Sink.ignore());
CompletionStage<Integer> result = flow.run(mat);
assertEquals(new Integer(1), result.toCompletableFuture().get(3, TimeUnit.SECONDS));
}
@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 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 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));
}
@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 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 void demonstrateADetachedGraphStage() throws Exception {
// tests:
CompletionStage<Integer> result1 =
Source.from(Arrays.asList(1, 2, 3))
.via(new TwoBuffer<>())
.runFold(0, (acc, n) -> acc + n, mat);
assertEquals(new Integer(6), result1.toCompletableFuture().get(3, TimeUnit.SECONDS));
TestSubscriber.ManualProbe<Integer> subscriber = TestSubscriber.manualProbe(system);
TestPublisher.Probe<Integer> publisher = TestPublisher.probe(0, system);
RunnableGraph<NotUsed> flow2 =
Source.fromPublisher(publisher).via(new TwoBuffer<>()).to(Sink.fromSubscriber(subscriber));
flow2.run(mat);
Subscription sub = subscriber.expectSubscription();
// this happens even though the subscriber has not signalled any demand
publisher.sendNext(1);
publisher.sendNext(2);
sub.cancel();
}