dimap
Transform this Flow by applying a function f
to each incoming upstream element before it is passed to the Flow, and a function g
to each outgoing downstream element.
Signature
Description
Transform this Flow by applying a function f
to each incoming upstream element before it is passed to the Flow, and a function g
to each outgoing downstream element.
Examples
- Scala
-
source
import org.apache.pekko import pekko.NotUsed import pekko.actor.ActorSystem import pekko.stream.scaladsl._ val source = Source(List("1", "2", "3")) val flow: Flow[Int, Int, NotUsed] = Flow[Int].map(_ * 2) val newFlow: Flow[String, String, NotUsed] = flow.dimap(Integer.parseInt)(_.toString) source.via(newFlow).runForeach(println) // expected prints: // 2 // 4 // 6
- Java
-
source
import org.apache.pekko.NotUsed; import org.apache.pekko.actor.ActorSystem; import org.apache.pekko.stream.javadsl.Flow; import org.apache.pekko.stream.javadsl.Source; import java.util.Arrays; final Source<String, NotUsed> source = Source.from(Arrays.asList("1", "2", "3")); final Flow<Integer, Integer, NotUsed> flow = Flow.<Integer>create().map(elem -> elem * 2); source .via(flow.dimap(Integer::parseInt, String::valueOf)) .runForeach(System.out::println, system); // expected prints: // 2 // 4 // 6
Reactive Streams semantics
emits when the mapping function g
returns an element
backpressures ’‘‘Backpressures when’’’ original flow backpressures
completes when original flow completes
cancels when original flow cancels
1.1.2+24-bcd44ee3*