akka.actor
Interface Stash
- All Superinterfaces:
- Actor, RequiresMessageQueue<DequeBasedMessageQueueSemantics>, UnrestrictedStash
- All Known Subinterfaces:
- Creators.ActWithStash
- All Known Implementing Classes:
- UntypedActorWithStash
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
.