future

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

Source operators

def future[T](futureElement: Future[T]): Source[T, NotUsed]

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

import akka.actor.ActorSystem
import akka.stream.scaladsl._
import akka.{ 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