akka.actor
Interface Stash

All Superinterfaces:

Actor, RequiresMessageQueue<DequeBasedMessageQueueSemantics>, StashSupport, UnrestrictedStash

All Known Subinterfaces:

AsyncWriteProxy, AtLeastOnceDelivery, Creators.ActWithStash, Eventsourced, EventsourcedProcessor, PersistentActor, PersistentView, Processor, ProcessorImpl, Recovery, View

All Known Implementing Classes:

AbstractActorWithStash, AbstractEventsourcedProcessor, AbstractPersistentActor, AbstractPersistentActorWithAtLeastOnceDelivery, AbstractPersistentView, AbstractProcessor, AbstractView, ClusterClient, ClusterSingletonProxy, InmemJournal, JournalPerfSpec.BenchActor, RequestReader, RequestWriter, ShardCoordinator, SharedLeveldbJournal, UntypedActorWithStash, UntypedEventsourcedProcessor, UntypedPersistentActor, UntypedPersistentActorWithAtLeastOnceDelivery, UntypedPersistentView, UntypedProcessor, UntypedView

public interface Stash
extends UnrestrictedStash, RequiresMessageQueue<DequeBasedMessageQueueSemantics>

The Stash trait enables an actor to temporarily stash away messages that can not or should not be handled using the actor's current behavior.

Example:

    class ActorWithProtocol extends Actor with Stash {
      def receive = {
        case "open" ⇒
          unstashAll()
          context.become({
            case "write" ⇒ // do writing...
            case "close" ⇒
              unstashAll()
              context.unbecome()
            case msg ⇒ stash()
          }, discardOld = false)
        case "done" ⇒ // done
        case msg    ⇒ stash()
      }
    }
  

Note that the Stash trait can only be used together with actors that have a deque-based mailbox. By default Stash based actors request a Deque based mailbox since the stash trait extends RequiresMessageQueue[DequeBasedMessageQueueSemantics]. You can override the default mailbox provided when DequeBasedMessageQueueSemantics are requested via config:

    akka.actor.mailbox.requirements {
      "akka.dispatch.BoundedDequeBasedMessageQueueSemantics" = your-custom-mailbox
    }
  

Alternatively, you can add your own requirement marker to the actor and configure a mailbox type to be used for your marker.

For a Stash that also enforces unboundedness of the deque see UnboundedStash. For a Stash that does not enforce any mailbox type see UnrestrictedStash.

Note that the Stash trait must be mixed into (a subclass of) the Actor trait before any trait/class that overrides the preRestart callback. This means it's not possible to write Actor with MyActor with Stash if MyActor overrides preRestart.

Nested Class Summary

Nested classes/interfaces inherited from interface akka.actor.Actor

Actor.emptyBehavior$

Method Summary

Methods inherited from interface akka.actor.UnrestrictedStash

postStop, preRestart

Methods inherited from interface akka.actor.Actor

aroundPostRestart, aroundPostStop, aroundPreRestart, aroundPreStart, aroundReceive, context, postRestart, preStart, receive, self, sender, supervisorStrategy, unhandled

Methods inherited from interface akka.actor.StashSupport

actorCell, capacity, clearStash, context, enqueueFirst, mailbox, prepend, self, stash, theStash, unstash, unstashAll, unstashAll