Source.future

Send the single value of the Future when it completes and there is demand.

Source operators

Signature¶

Source.futureSource.future

Description¶

Send the single value of the Future when it completes and there is demand. If the future fails the stream is failed with that exception.

For the corresponding operator for the Java standard library CompletionStage see completionStage.

Example¶

Scala

copysource
import org.apache.pekko
import pekko.actor.ActorSystem
import pekko.stream.scaladsl._
import pekko.{ Done, NotUsed }

import scala.concurrent.Future

val source: Source[Int, NotUsed] = Source.future(Future.successful(10))
val sink: Sink[Int, Future[Done]] = Sink.foreach((i: Int) => println(i))

val done: Future[Done] = source.runWith(sink) // 10

Reactive Streams semantics¶