ask
Use the “Ask Pattern” to send a request-reply message to the target ref actor (of the classic actors API).
Signature
Source.askSource.ask Flow.askFlow.ask
Description
Use the Ask Pattern to send a request-reply message to the target ref actor. If any of the asks times out it will fail the stream with a AskTimeoutExceptionAskTimeoutException.
The mapTo classS generic parameter is used to cast the responses from the actor to the expected outgoing flow type.
Similar to the plain ask pattern, the target actor is allowed to reply with StatusStatus. An FailureFailure will cause the operator to fail with the cause carried in the Failure message.
Adheres to the ActorAttributes.SupervisionStrategyActorAttributes.SupervisionStrategy attribute.
See also:
- ActorFlow.ask for the
akka.actor.typed.ActorRef[_]variant
Reactive Streams semantics
emits when the ask Future CompletionStage returned by the provided function finishes for the next element in sequence
backpressures when the number of ask Future s CompletionStage s reaches the configured parallelism and the downstream backpressures
completes when upstream completes and all ask Future s CompletionStage s has been completed and all elements has been emitted