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!str #16168: Expose materialized value in the graph as a "source"

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Endre Sándor Varga 2015-03-30 14:22:12 +02:00
parent 37aa2cb886
commit a7af773e2c
33 changed files with 601 additions and 173 deletions
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35
akka-docs-dev/rst/scala/code/docs/stream/FlowGraphDocSpec.scala
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@ -8,7 +8,7 @@ import akka.stream.scaladsl._
import akka.stream.testkit.AkkaSpec
import scala.collection.immutable
import scala.concurrent.Await
import scala.concurrent.{ Future, Await }
import scala.concurrent.duration._
class FlowGraphDocSpec extends AkkaSpec {
@ -20,7 +20,7 @@ class FlowGraphDocSpec extends AkkaSpec {
"build simple graph" in {
//format: OFF
//#simple-flow-graph
val g = FlowGraph.closed() { implicit builder: FlowGraph.Builder =>
val g = FlowGraph.closed() { implicit builder: FlowGraph.Builder[Unit] =>
import FlowGraph.Implicits._
val in = Source(1 to 10)
val out = Sink.ignore
@ -43,7 +43,7 @@ class FlowGraphDocSpec extends AkkaSpec {
"build simple graph without implicits" in {
//#simple-flow-graph-no-implicits
val g = FlowGraph.closed() { builder: FlowGraph.Builder =>
val g = FlowGraph.closed() { builder: FlowGraph.Builder[Unit] =>
val in = Source(1 to 10)
val out = Sink.ignore
@ -219,4 +219,33 @@ class FlowGraphDocSpec extends AkkaSpec {
}
"access to materialized value" in {
//#flow-graph-matvalue
import FlowGraph.Implicits._
val foldFlow: Flow[Int, Int, Future[Int]] = Flow(Sink.fold[Int, Int](0)(_ + _)) {
implicit builder ⇒
fold ⇒
(fold.inlet, builder.matValue.mapAsync(identity).outlet)
}
//#flow-graph-matvalue
Await.result(Source(1 to 10).via(foldFlow).runWith(Sink.head), 3.seconds) should ===(55)
//#flow-graph-matvalue-cycle
import FlowGraph.Implicits._
// This cannot produce any value:
val cyclicFold: Source[Int, Future[Int]] = Source(Sink.fold[Int, Int](0)(_ + _)) {
implicit builder =>
fold =>
// - Fold cannot complete until its upstream mapAsync completes
// - mapAsync cannot complete until the materialized Future produced by
// fold completes
// As a result this Source will never emit anything, and its materialited
// Future will never complete
builder.matValue.mapAsync(identity) ~> fold
builder.matValue.mapAsync(identity).outlet
}
//#flow-graph-matvalue-cycle
}
}