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 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 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));
}
public void run(final Materializer mat)
throws TimeoutException, InterruptedException, ExecutionException {
// #backpressure-by-readline
final CompletionStage<Done> completion =
Source.from(Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
.map(
i -> {
System.out.println("map => " + i);
return i;
})
.runForeach(
i ->
System.console()
.readLine("Element = %s continue reading? [press enter]\n", i),
mat);
completion.toCompletableFuture().get(1, TimeUnit.SECONDS);
// #backpressure-by-readline
}
@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();
}
public void requestExamples() {
// #ws-holder
WSRequest request = ws.url("http://example.com");
// #ws-holder
// #ws-complex-holder
WSRequest complexRequest =
request
.setHeader("headerKey", "headerValue")
.setRequestTimeout(1000)
.setQueryParameter("paramKey", "paramValue");
// #ws-complex-holder
// #ws-get
CompletionStage<WSResponse> responsePromise = complexRequest.get();
// #ws-get
String url = "http://example.com";
// #ws-auth
ws.url(url).setAuth("user", "password", WSAuthScheme.BASIC).get();
// #ws-auth
// #ws-follow-redirects
ws.url(url).setFollowRedirects(true).get();
// #ws-follow-redirects
// #ws-query-parameter
ws.url(url).setQueryParameter("paramKey", "paramValue");
// #ws-query-parameter
// #ws-header
ws.url(url).setHeader("headerKey", "headerValue").get();
// #ws-header
String jsonString = "{\"key1\":\"value1\"}";
// #ws-header-content-type
ws.url(url).setHeader("Content-Type", "application/json").post(jsonString);
// OR
ws.url(url).setContentType("application/json").post(jsonString);
// #ws-header-content-type
// #ws-timeout
ws.url(url).setRequestTimeout(1000).get();
// #ws-timeout
// #ws-post-form-data
ws.url(url)
.setContentType("application/x-www-form-urlencoded")
.post("key1=value1&key2=value2");
// #ws-post-form-data
// #ws-post-json
JsonNode json = Json.newObject().put("key1", "value1").put("key2", "value2");
ws.url(url).post(json);
// #ws-post-json
String value =
IntStream.range(0, 100).boxed().map(i -> "abcdefghij").reduce("", (a, b) -> a + b);
ByteString seedValue = ByteString.fromString(value);
Stream<ByteString> largeSource = IntStream.range(0, 10).boxed().map(i -> seedValue);
Source<ByteString, ?> largeImage = Source.from(largeSource.collect(Collectors.toList()));
// #ws-stream-request
CompletionStage<WSResponse> wsResponse = ws.url(url).setBody(largeImage).execute("PUT");
// #ws-stream-request
}
abstract static class Model {
// #model
public static class Author {
public final String handle;
public Author(String handle) {
this.handle = handle;
}
// ...
// #model
@Override
public String toString() {
return "Author(" + handle + ")";
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
Author author = (Author) o;
if (handle != null ? !handle.equals(author.handle) : author.handle != null) {
return false;
}
return true;
}
@Override
public int hashCode() {
return handle != null ? handle.hashCode() : 0;
}
// #model
}
// #model
// #model
public static class Hashtag {
public final String name;
public Hashtag(String name) {
this.name = name;
}
// ...
// #model
@Override
public int hashCode() {
return name.hashCode();
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
Hashtag other = (Hashtag) obj;
return name.equals(other.name);
}
@Override
public String toString() {
return "Hashtag(" + name + ")";
}
// #model
}
// #model
// #model
public static class Tweet {
public final Author author;
public final long timestamp;
public final String body;
public Tweet(Author author, long timestamp, String body) {
this.author = author;
this.timestamp = timestamp;
this.body = body;
}
public Set<Hashtag> hashtags() {
return Arrays.asList(body.split(" "))
.stream()
.filter(a -> a.startsWith("#"))
.map(a -> new Hashtag(a))
.collect(Collectors.toSet());
}
// ...
// #model
@Override
public String toString() {
return "Tweet(" + author + "," + timestamp + "," + body + ")";
}
// #model
}
// #model
// #model
public static final Hashtag AKKA = new Hashtag("#akka");
// #model
public static final Source<Tweet, NotUsed> tweets =
Source.from(
Arrays.asList(
new Tweet[] {
new Tweet(new Author("rolandkuhn"), System.currentTimeMillis(), "#akka rocks!"),
new Tweet(new Author("patriknw"), System.currentTimeMillis(), "#akka !"),
new Tweet(new Author("bantonsson"), System.currentTimeMillis(), "#akka !"),
new Tweet(new Author("drewhk"), System.currentTimeMillis(), "#akka !"),
new Tweet(
new Author("ktosopl"), System.currentTimeMillis(), "#akka on the rocks!"),
new Tweet(new Author("mmartynas"), System.currentTimeMillis(), "wow #akka !"),
new Tweet(new Author("akkateam"), System.currentTimeMillis(), "#akka rocks!"),
new Tweet(new Author("bananaman"), System.currentTimeMillis(), "#bananas rock!"),
new Tweet(new Author("appleman"), System.currentTimeMillis(), "#apples rock!"),
new Tweet(
new Author("drama"),
System.currentTimeMillis(),
"we compared #apples to #oranges!")
}));
}
