actorRefWithAck

Materialize an ActorRef; sending messages to it will emit them on the stream. The source acknowledges reception after emitting a message, to provide back pressure from the source.

Source operators

Signature

def actorRefWithAck[T](ackMessage: Any): Source[T, ActorRef]

Description

Materialize an ActorRef, sending messages to it will emit them on the stream. The actor responds with the provided ack message once the element could be emitted alowing for backpressure from the source. Sending another message before the previous one has been acknowledged will fail the stream.

emits when there is demand and there are messages in the buffer or a message is sent to the ActorRef

completes when the ActorRef is sent akka.actor.Status.Success

Examples

Scala

import akka.actor.Status.Success import akka.actor.ActorRef import akka.stream.CompletionStrategy import akka.stream.scaladsl._ implicit val system: ActorSystem = ActorSystem() implicit val materializer: ActorMaterializer = ActorMaterializer() val probe = TestProbe() val source: Source[Any, ActorRef] = Source.actorRefWithAck[Any]("ack") val actorRef: ActorRef = source.to(Sink.foreach(println)).run() probe.send(actorRef, "hello") probe.expectMsg("ack") probe.send(actorRef, "hello") probe.expectMsg("ack") // The stream completes successfully with the following message actorRef ! Success(CompletionStrategy.immediately)
Java
import akka.actor.ActorRef;
import akka.actor.Status.Success;
import akka.stream.OverflowStrategy;
import akka.stream.CompletionStrategy;
import akka.stream.javadsl.Sink;
import akka.testkit.TestProbe;
final ActorSystem system = ActorSystem.create();
final Materializer materializer = ActorMaterializer.create(system);

Source<Object, ActorRef> source = Source.actorRefWithAck("ack");

ActorRef actorRef = source.to(Sink.foreach(System.out::println)).run(materializer);
probe.send(actorRef, "hello");
probe.expectMsg("ack");
probe.send(actorRef, "hello");
probe.expectMsg("ack");

// The stream completes successfully with the following message
actorRef.tell(new Success(CompletionStrategy.draining()), ActorRef.noSender());
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