@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 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 mustWorkFromFuture() throws Exception {
final Iterable<String> input = Arrays.asList("A", "B", "C");
CompletionStage<String> future1 = Source.from(input).runWith(Sink.<String>head(), materializer);
CompletionStage<String> future2 =
Source.fromCompletionStage(future1).runWith(Sink.<String>head(), materializer);
String result = future2.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals("A", result);
}
@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 mustProduceTicks() throws Exception {
final JavaTestKit probe = new JavaTestKit(system);
Source<String, Cancellable> tickSource =
Source.tick(
FiniteDuration.create(1, TimeUnit.SECONDS),
FiniteDuration.create(500, TimeUnit.MILLISECONDS),
"tick");
@SuppressWarnings("unused")
Cancellable cancellable =
tickSource
.to(
Sink.foreach(
new Procedure<String>() {
public void apply(String elem) {
probe.getRef().tell(elem, ActorRef.noSender());
}
}))
.run(materializer);
probe.expectNoMsg(FiniteDuration.create(600, TimeUnit.MILLISECONDS));
probe.expectMsgEquals("tick");
probe.expectNoMsg(FiniteDuration.create(200, TimeUnit.MILLISECONDS));
probe.expectMsgEquals("tick");
probe.expectNoMsg(FiniteDuration.create(200, TimeUnit.MILLISECONDS));
}
@Test
public void mustBeAbleToRecover() throws Exception {
final ManualProbe<Integer> publisherProbe = TestPublisher.manualProbe(true, system);
final JavaTestKit probe = new JavaTestKit(system);
final Source<Integer, NotUsed> source =
Source.fromPublisher(publisherProbe)
.map(
elem -> {
if (elem == 1) throw new RuntimeException("ex");
else return elem;
})
.recover(new PFBuilder<Throwable, Integer>().matchAny(ex -> 0).build());
final CompletionStage<Done> future =
source.runWith(
Sink.foreach(elem -> probe.getRef().tell(elem, ActorRef.noSender())), materializer);
final PublisherProbeSubscription<Integer> s = publisherProbe.expectSubscription();
s.sendNext(0);
probe.expectMsgEquals(0);
s.sendNext(1);
probe.expectMsgEquals(0);
future.toCompletableFuture().get(200, TimeUnit.MILLISECONDS);
}
@Test
public void mustBeAbleToUseFlatMapMerge() throws Exception {
final JavaTestKit probe = new JavaTestKit(system);
final Iterable<Integer> input1 = Arrays.asList(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
final Iterable<Integer> input2 = Arrays.asList(10, 11, 12, 13, 14, 15, 16, 17, 18, 19);
final Iterable<Integer> input3 = Arrays.asList(20, 21, 22, 23, 24, 25, 26, 27, 28, 29);
final Iterable<Integer> input4 = Arrays.asList(30, 31, 32, 33, 34, 35, 36, 37, 38, 39);
final List<Source<Integer, NotUsed>> mainInputs = new ArrayList<Source<Integer, NotUsed>>();
mainInputs.add(Source.from(input1));
mainInputs.add(Source.from(input2));
mainInputs.add(Source.from(input3));
mainInputs.add(Source.from(input4));
CompletionStage<List<Integer>> future =
Source.from(mainInputs)
.flatMapMerge(3, ConstantFun.<Source<Integer, NotUsed>>javaIdentityFunction())
.grouped(60)
.runWith(Sink.<List<Integer>>head(), materializer);
List<Integer> result = future.toCompletableFuture().get(3, TimeUnit.SECONDS);
final Set<Integer> set = new HashSet<Integer>();
for (Integer i : result) {
set.add(i);
}
final Set<Integer> expected = new HashSet<Integer>();
for (int i = 0; i < 40; ++i) {
expected.add(i);
}
assertEquals(expected, set);
}
@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 mustRepeat() throws Exception {
final CompletionStage<List<Integer>> f =
Source.repeat(42).grouped(10000).runWith(Sink.<List<Integer>>head(), materializer);
final List<Integer> result = f.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals(result.size(), 10000);
for (Integer i : result) assertEquals(i, (Integer) 42);
}
@Test
public void mustBeAbleToUsePrefixAndTail() throws Exception {
final JavaTestKit probe = new JavaTestKit(system);
final Iterable<Integer> input = Arrays.asList(1, 2, 3, 4, 5, 6);
CompletionStage<Pair<List<Integer>, Source<Integer, NotUsed>>> future =
Source.from(input)
.prefixAndTail(3)
.runWith(Sink.<Pair<List<Integer>, Source<Integer, NotUsed>>>head(), materializer);
Pair<List<Integer>, Source<Integer, NotUsed>> result =
future.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals(Arrays.asList(1, 2, 3), result.first());
CompletionStage<List<Integer>> tailFuture =
result.second().limit(4).runWith(Sink.<Integer>seq(), materializer);
List<Integer> tailResult = tailFuture.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals(Arrays.asList(4, 5, 6), tailResult);
}
@Test
public void mustBeAbleToUseToFuture() throws Exception {
final JavaTestKit probe = new JavaTestKit(system);
final Iterable<String> input = Arrays.asList("A", "B", "C");
CompletionStage<String> future = Source.from(input).runWith(Sink.<String>head(), materializer);
String result = future.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals("A", result);
}
@Test
public void mustWorkFromRange() throws Exception {
CompletionStage<List<Integer>> f =
Source.range(0, 10).grouped(20).runWith(Sink.<List<Integer>>head(), materializer);
final List<Integer> result = f.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals(11, result.size());
Integer counter = 0;
for (Integer i : result) assertEquals(i, counter++);
}
@Test
public void demonstrateSlowProcessing() {
// #tweets-slow-consumption-dropHead
tweets
.buffer(10, OverflowStrategy.dropHead())
.map(t -> slowComputation(t))
.runWith(Sink.ignore(), mat);
// #tweets-slow-consumption-dropHead
}
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 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 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 mustBeAbleToUseThrottle() throws Exception {
Integer result =
Source.from(Arrays.asList(0, 1, 2))
.throttle(10, FiniteDuration.create(1, TimeUnit.SECONDS), 10, ThrottleMode.shaping())
.throttle(10, FiniteDuration.create(1, TimeUnit.SECONDS), 10, ThrottleMode.enforcing())
.runWith(Sink.head(), materializer)
.toCompletableFuture()
.get(3, TimeUnit.SECONDS);
assertEquals((Object) 0, result);
}
@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 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 mustBeAbleToUseBuffer() throws Exception {
final JavaTestKit probe = new JavaTestKit(system);
final List<String> input = Arrays.asList("A", "B", "C");
final CompletionStage<List<String>> future =
Source.from(input)
.buffer(2, OverflowStrategy.backpressure())
.grouped(4)
.runWith(Sink.<List<String>>head(), materializer);
List<String> result = future.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals(input, result);
}
@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 mustBeAbleToUseIdleTimeout() throws Throwable {
try {
try {
Source.maybe()
.idleTimeout(Duration.create(1, "second"))
.runWith(Sink.head(), materializer)
.toCompletableFuture()
.get(3, TimeUnit.SECONDS);
fail("A TimeoutException was expected");
} catch (ExecutionException e) {
throw e.getCause();
}
} catch (TimeoutException e) {
// expected
}
}
@Test
public void mustBeAbleToUseOnCompleteSuccess() {
final JavaTestKit probe = new JavaTestKit(system);
final Iterable<String> input = Arrays.asList("A", "B", "C");
Source.from(input)
.runWith(
Sink.<String>onComplete(
new Procedure<Try<Done>>() {
@Override
public void apply(Try<Done> param) throws Exception {
probe.getRef().tell(param.get(), ActorRef.noSender());
}
}),
materializer);
probe.expectMsgClass(Done.class);
}
@Test
public void mustBeAbleToUseIdleInject() throws Exception {
Integer result =
Source.maybe()
.keepAlive(
Duration.create(1, "second"),
new Creator<Integer>() {
public Integer create() {
return 0;
}
})
.takeWithin(Duration.create(1500, "milliseconds"))
.runWith(Sink.<Integer>head(), materializer)
.toCompletableFuture()
.get(3, TimeUnit.SECONDS);
assertEquals((Object) 0, result);
}
@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 mustBeAbleToUseActorRefSource() throws Exception {
final JavaTestKit probe = new JavaTestKit(system);
final Source<Integer, ActorRef> actorRefSource = Source.actorRef(10, OverflowStrategy.fail());
final ActorRef ref =
actorRefSource
.to(
Sink.foreach(
new Procedure<Integer>() {
public void apply(Integer elem) {
probe.getRef().tell(elem, ActorRef.noSender());
}
}))
.run(materializer);
ref.tell(1, ActorRef.noSender());
probe.expectMsgEquals(1);
ref.tell(2, ActorRef.noSender());
probe.expectMsgEquals(2);
}
@Test
public void mustBeAbleToUseDropWhile() throws Exception {
final JavaTestKit probe = new JavaTestKit(system);
final Source<Integer, NotUsed> source =
Source.from(Arrays.asList(0, 1, 2, 3))
.dropWhile(
new Predicate<Integer>() {
public boolean test(Integer elem) {
return elem < 2;
}
});
final CompletionStage<Done> future =
source.runWith(
Sink.foreach(elem -> probe.getRef().tell(elem, ActorRef.noSender())), materializer);
probe.expectMsgEquals(2);
probe.expectMsgEquals(3);
future.toCompletableFuture().get(200, TimeUnit.MILLISECONDS);
}
@Test
public void demonstrateFilterAndMap() {
final SilenceSystemOut.System System = SilenceSystemOut.get();
// #first-sample
// #authors-filter-map
final Source<Author, NotUsed> authors =
tweets.filter(t -> t.hashtags().contains(AKKA)).map(t -> t.author);
// #first-sample
// #authors-filter-map
new Object() {
// #authors-collect
JavaPartialFunction<Tweet, Author> collectFunction =
new JavaPartialFunction<Tweet, Author>() {
public Author apply(Tweet t, boolean isCheck) {
if (t.hashtags().contains(AKKA)) {
if (isCheck) return null; // to spare the expensive or side-effecting code
return t.author;
} else {
throw noMatch();
}
}
};
final Source<Author, NotUsed> authors = tweets.collect(collectFunction);
// #authors-collect
};
// #first-sample
// #authors-foreachsink-println
authors.runWith(Sink.foreach(a -> System.out.println(a)), mat);
// #first-sample
// #authors-foreachsink-println
// #authors-foreach-println
authors.runForeach(a -> System.out.println(a), mat);
// #authors-foreach-println
}
@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
};
}
