// #timed
// each time an event is pushed through it will trigger a period of silence
public class TimedGate<A> extends GraphStage<FlowShape<A, A>> {
private final FiniteDuration silencePeriod;
public TimedGate(FiniteDuration silencePeriod) {
this.silencePeriod = silencePeriod;
}
public final Inlet<A> in = Inlet.create("TimedGate.in");
public final Outlet<A> out = Outlet.create("TimedGate.out");
private final FlowShape<A, A> shape = FlowShape.of(in, out);
@Override
public FlowShape<A, A> shape() {
return shape;
}
@Override
public GraphStageLogic createLogic(Attributes inheritedAttributes) {
return new TimerGraphStageLogic(shape) {
private boolean open = false;
{
setHandler(
in,
new AbstractInHandler() {
@Override
public void onPush() {
A elem = grab(in);
if (open) pull(in);
else {
push(out, elem);
open = true;
scheduleOnce("key", silencePeriod);
}
}
});
setHandler(
out,
new AbstractOutHandler() {
@Override
public void onPull() {
pull(in);
}
});
}
@Override
public void onTimer(Object key) {
if (key.equals("key")) {
open = false;
}
}
};
}
}
// #materialized
public class FirstValue<A>
extends GraphStageWithMaterializedValue<FlowShape<A, A>, CompletionStage<A>> {
public final Inlet<A> in = Inlet.create("FirstValue.in");
public final Outlet<A> out = Outlet.create("FirstValue.out");
private final FlowShape<A, A> shape = FlowShape.of(in, out);
@Override
public FlowShape<A, A> shape() {
return shape;
}
@Override
public Tuple2<GraphStageLogic, CompletionStage<A>> createLogicAndMaterializedValue(
Attributes inheritedAttributes) {
Promise<A> promise = Futures.promise();
GraphStageLogic logic =
new GraphStageLogic(shape) {
{
setHandler(
in,
new AbstractInHandler() {
@Override
public void onPush() {
A elem = grab(in);
promise.success(elem);
push(out, elem);
// replace handler with one just forwarding
setHandler(
in,
new AbstractInHandler() {
@Override
public void onPush() {
push(out, grab(in));
}
});
}
});
setHandler(
out,
new AbstractOutHandler() {
@Override
public void onPull() {
pull(in);
}
});
}
};
return new Tuple2(logic, promise.future());
}
}
// #async-side-channel
// will close upstream when the future completes
public class KillSwitch<A> extends GraphStage<FlowShape<A, A>> {
private final CompletionStage<Done> switchF;
public KillSwitch(CompletionStage<Done> switchF) {
this.switchF = switchF;
}
public final Inlet<A> in = Inlet.create("KillSwitch.in");
public final Outlet<A> out = Outlet.create("KillSwitch.out");
private final FlowShape<A, A> shape = FlowShape.of(in, out);
@Override
public FlowShape<A, A> shape() {
return shape;
}
@Override
public GraphStageLogic createLogic(Attributes inheritedAttributes) {
return new GraphStageLogic(shape) {
{
setHandler(
in,
new AbstractInHandler() {
@Override
public void onPush() {
push(out, grab(in));
}
});
setHandler(
out,
new AbstractOutHandler() {
@Override
public void onPull() {
pull(in);
}
});
}
@Override
public void preStart() {
AsyncCallback<Done> callback =
createAsyncCallback(
new Procedure<Done>() {
@Override
public void apply(Done param) throws Exception {
completeStage();
}
});
ExecutionContext ec = system.dispatcher();
switchF.thenAccept(callback::invoke);
}
};
}
}
// #one-to-many
public class Duplicator<A> extends GraphStage<FlowShape<A, A>> {
public final Inlet<A> in = Inlet.create("Duplicator.in");
public final Outlet<A> out = Outlet.create("Duplicator.out");
private final FlowShape<A, A> shape = FlowShape.of(in, out);
@Override
public FlowShape<A, A> shape() {
return shape;
}
public GraphStageLogic createLogic(Attributes inheritedAttributes) {
return new GraphStageLogic(shape) {
// Again: note that all mutable state
// MUST be inside the GraphStageLogic
Option<A> lastElem = Option.none();
{
setHandler(
in,
new AbstractInHandler() {
@Override
public void onPush() {
A elem = grab(in);
lastElem = Option.some(elem);
push(out, elem);
}
@Override
public void onUpstreamFinish() {
if (lastElem.isDefined()) {
emit(out, lastElem.get());
}
complete(out);
}
});
setHandler(
out,
new AbstractOutHandler() {
@Override
public void onPull() {
if (lastElem.isDefined()) {
push(out, lastElem.get());
lastElem = Option.none();
} else {
pull(in);
}
}
});
}
};
}
}
// #many-to-one
public final class Filter<A> extends GraphStage<FlowShape<A, A>> {
private final Predicate<A> p;
public Filter(Predicate<A> p) {
this.p = p;
}
public final Inlet<A> in = Inlet.create("Filter.in");
public final Outlet<A> out = Outlet.create("Filter.out");
private final FlowShape<A, A> shape = FlowShape.of(in, out);
@Override
public FlowShape<A, A> shape() {
return shape;
}
public GraphStageLogic createLogic(Attributes inheritedAttributes) {
return new GraphStageLogic(shape) {
{
setHandler(
in,
new AbstractInHandler() {
@Override
public void onPush() {
A elem = grab(in);
if (p.test(elem)) {
push(out, elem);
} else {
pull(in);
}
}
});
setHandler(
out,
new AbstractOutHandler() {
@Override
public void onPull() {
pull(in);
}
});
}
};
}
}
// #one-to-one
public class Map<A, B> extends GraphStage<FlowShape<A, B>> {
private final Function<A, B> f;
public Map(Function<A, B> f) {
this.f = f;
}
public final Inlet<A> in = Inlet.create("Map.in");
public final Outlet<B> out = Outlet.create("Map.out");
private final FlowShape<A, B> shape = FlowShape.of(in, out);
@Override
public FlowShape<A, B> shape() {
return shape;
}
@Override
public GraphStageLogic createLogic(Attributes inheritedAttributes) {
return new GraphStageLogic(shape) {
{
setHandler(
in,
new AbstractInHandler() {
@Override
public void onPush() {
try {
push(out, f.apply(grab(in)));
} catch (Exception ex) {
failStage(ex);
}
}
});
setHandler(
out,
new AbstractOutHandler() {
@Override
public void onPull() {
pull(in);
}
});
}
};
}
}
// #worker-pool
public static <In, Out> Flow<In, Out, BoxedUnit> balancer(
Flow<In, Out, BoxedUnit> worker, int workerCount) {
return Flow.fromGraph(
GraphDSL.create(
b -> {
boolean waitForAllDownstreams = true;
final UniformFanOutShape<In, In> balance =
b.add(Balance.<In>create(workerCount, waitForAllDownstreams));
final UniformFanInShape<Out, Out> merge = b.add(Merge.<Out>create(workerCount));
for (int i = 0; i < workerCount; i++) {
b.from(balance.out(i)).via(b.add(worker)).toInlet(merge.in(i));
}
return FlowShape.of(balance.in(), merge.out());
}));
}
// #simpler-one-to-many
public class Duplicator2<A> extends GraphStage<FlowShape<A, A>> {
public final Inlet<A> in = Inlet.create("Duplicator.in");
public final Outlet<A> out = Outlet.create("Duplicator.out");
private final FlowShape<A, A> shape = FlowShape.of(in, out);
@Override
public FlowShape<A, A> shape() {
return shape;
}
@Override
public GraphStageLogic createLogic(Attributes inheritedAttributes) {
return new GraphStageLogic(shape) {
{
setHandler(
in,
new AbstractInHandler() {
@Override
public void onPush() {
A elem = grab(in);
// this will temporarily suspend this handler until the two elems
// are emitted and then reinstates it
emitMultiple(out, Arrays.asList(elem, elem).iterator());
}
});
setHandler(
out,
new AbstractOutHandler() {
@Override
public void onPull() {
pull(in);
}
});
}
};
}
}
// #detached
public class TwoBuffer<A> extends GraphStage<FlowShape<A, A>> {
public final Inlet<A> in = Inlet.create("TwoBuffer.in");
public final Outlet<A> out = Outlet.create("TwoBuffer.out");
private final FlowShape<A, A> shape = FlowShape.of(in, out);
@Override
public FlowShape<A, A> shape() {
return shape;
}
@Override
public GraphStageLogic createLogic(Attributes inheritedAttributes) {
return new GraphStageLogic(shape) {
private final int SIZE = 2;
private Queue<A> buffer = new ArrayDeque<>(SIZE);
private boolean downstreamWaiting = false;
private boolean isBufferFull() {
return buffer.size() == SIZE;
}
@Override
public void preStart() {
// a detached stage needs to start upstream demand
// itself as it is not triggered by downstream demand
pull(in);
}
{
setHandler(
in,
new AbstractInHandler() {
@Override
public void onPush() {
A elem = grab(in);
buffer.add(elem);
if (downstreamWaiting) {
downstreamWaiting = false;
A bufferedElem = buffer.poll();
push(out, bufferedElem);
}
if (!isBufferFull()) {
pull(in);
}
}
@Override
public void onUpstreamFinish() {
if (!buffer.isEmpty()) {
// emit the rest if possible
emitMultiple(out, buffer.iterator());
}
completeStage();
}
});
setHandler(
out,
new AbstractOutHandler() {
@Override
public void onPull() {
if (buffer.isEmpty()) {
downstreamWaiting = true;
} else {
A elem = buffer.poll();
push(out, elem);
}
if (!isBufferFull() && !hasBeenPulled(in)) {
pull(in);
}
}
});
}
};
}
}
public static void main(String[] args) {
Outlet<Integer> outlet = null;
Outlet<Integer> outlet1 = null;
Outlet<Integer> outlet2 = null;
Inlet<Integer> inlet = null;
Inlet<Integer> inlet1 = null;
Inlet<Integer> inlet2 = null;
Flow<Integer, Integer, BoxedUnit> flow = Flow.of(Integer.class);
Flow<Integer, Integer, BoxedUnit> flow1 = Flow.of(Integer.class);
Flow<Integer, Integer, BoxedUnit> flow2 = Flow.of(Integer.class);
Promise<Option<Integer>> promise = null;
{
Graph<SourceShape<Integer>, BoxedUnit> graphSource = null;
Graph<SinkShape<Integer>, BoxedUnit> graphSink = null;
Graph<FlowShape<Integer, Integer>, BoxedUnit> graphFlow = null;
// #flow-wrap
Source<Integer, BoxedUnit> source = Source.fromGraph(graphSource);
Sink<Integer, BoxedUnit> sink = Sink.fromGraph(graphSink);
Flow<Integer, Integer, BoxedUnit> aflow = Flow.fromGraph(graphFlow);
Flow.fromSinkAndSource(Sink.<Integer>head(), Source.single(0));
Flow.fromSinkAndSourceMat(Sink.<Integer>head(), Source.single(0), Keep.left());
// #flow-wrap
Graph<BidiShape<Integer, Integer, Integer, Integer>, BoxedUnit> bidiGraph = null;
// #bidi-wrap
BidiFlow<Integer, Integer, Integer, Integer, BoxedUnit> bidiFlow =
BidiFlow.fromGraph(bidiGraph);
BidiFlow.fromFlows(flow1, flow2);
BidiFlow.fromFlowsMat(flow1, flow2, Keep.both());
// #bidi-wrap
}
{
// #graph-create
GraphDSL.create(
builder -> {
// ...
return ClosedShape.getInstance();
});
GraphDSL.create(
builder -> {
// ...
return new FlowShape<>(inlet, outlet);
});
// #graph-create
}
{
// #graph-create-2
GraphDSL.create(
builder -> {
// ...
return SourceShape.of(outlet);
});
GraphDSL.create(
builder -> {
// ...
return SinkShape.of(inlet);
});
GraphDSL.create(
builder -> {
// ...
return FlowShape.of(inlet, outlet);
});
GraphDSL.create(
builder -> {
// ...
return BidiShape.of(inlet1, outlet1, inlet2, outlet2);
});
// #graph-create-2
}
{
// #graph-builder
GraphDSL.create(
builder -> {
builder.from(outlet).toInlet(inlet);
builder.from(outlet).via(builder.add(flow)).toInlet(inlet);
builder.from(builder.add(Source.single(0))).to(builder.add(Sink.head()));
// ...
return ClosedShape.getInstance();
});
// #graph-builder
}
// #source-creators
Source<Integer, Promise<Option<Integer>>> src = Source.<Integer>maybe();
// Complete the promise with an empty option to emulate the old lazyEmpty
promise.trySuccess(scala.Option.empty());
final Source<String, Cancellable> ticks =
Source.tick(
FiniteDuration.create(0, TimeUnit.MILLISECONDS),
FiniteDuration.create(200, TimeUnit.MILLISECONDS),
"tick");
final Source<Integer, BoxedUnit> pubSource =
Source.fromPublisher(TestPublisher.<Integer>manualProbe(true, sys));
final Source<Integer, BoxedUnit> futSource = Source.fromFuture(Futures.successful(42));
final Source<Integer, Subscriber<Integer>> subSource = Source.<Integer>asSubscriber();
// #source-creators
// #sink-creators
final Sink<Integer, BoxedUnit> subSink =
Sink.fromSubscriber(TestSubscriber.<Integer>manualProbe(sys));
// #sink-creators
// #sink-as-publisher
final Sink<Integer, Publisher<Integer>> pubSink = Sink.<Integer>asPublisher(false);
final Sink<Integer, Publisher<Integer>> pubSinkFanout = Sink.<Integer>asPublisher(true);
// #sink-as-publisher
// #empty-flow
Flow<Integer, Integer, BoxedUnit> emptyFlow = Flow.<Integer>create();
// or
Flow<Integer, Integer, BoxedUnit> emptyFlow2 = Flow.of(Integer.class);
// #empty-flow
// #flatMapConcat
Flow.<Source<Integer, BoxedUnit>>create()
.<Integer, BoxedUnit>flatMapConcat(
new Function<Source<Integer, BoxedUnit>, Source<Integer, BoxedUnit>>() {
@Override
public Source<Integer, BoxedUnit> apply(Source<Integer, BoxedUnit> param)
throws Exception {
return param;
}
});
// #flatMapConcat
Uri uri = null;
// #raw-query
final akka.japi.Option<String> theRawQueryString = uri.rawQueryString();
// #raw-query
// #query-param
final akka.japi.Option<String> aQueryParam = uri.query().get("a");
// #query-param
// #file-source-sink
final Source<ByteString, Future<Long>> fileSrc = FileIO.fromFile(new File("."));
final Source<ByteString, Future<Long>> otherFileSrc = FileIO.fromFile(new File("."), 1024);
final Sink<ByteString, Future<Long>> fileSink = FileIO.toFile(new File("."));
// #file-source-sink
// #input-output-stream-source-sink
final Source<ByteString, Future<java.lang.Long>> inputStreamSrc =
StreamConverters.fromInputStream(
new Creator<InputStream>() {
public InputStream create() {
return new SomeInputStream();
}
});
final Source<ByteString, Future<java.lang.Long>> otherInputStreamSrc =
StreamConverters.fromInputStream(
new Creator<InputStream>() {
public InputStream create() {
return new SomeInputStream();
}
},
1024);
final Sink<ByteString, Future<java.lang.Long>> outputStreamSink =
StreamConverters.fromOutputStream(
new Creator<OutputStream>() {
public OutputStream create() {
return new SomeOutputStream();
}
});
// #input-output-stream-source-sink
// #output-input-stream-source-sink
final FiniteDuration timeout = FiniteDuration.Zero();
final Source<ByteString, OutputStream> outputStreamSrc = StreamConverters.asOutputStream();
final Source<ByteString, OutputStream> otherOutputStreamSrc =
StreamConverters.asOutputStream(timeout);
final Sink<ByteString, InputStream> someInputStreamSink = StreamConverters.asInputStream();
final Sink<ByteString, InputStream> someOtherInputStreamSink =
StreamConverters.asInputStream(timeout);
// #output-input-stream-source-sink
}