Packages

trait Stash extends UnrestrictedStash with 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: 

   pekko.actor.mailbox.requirements {
     "org.apache.pekko.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 pekko.actor.UnboundedStash. For a Stash that does not enforce any mailbox type see pekko.actor.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.

Source
Stash.scala
Linear Supertypes
RequiresMessageQueue[DequeBasedMessageQueueSemantics], UnrestrictedStash, StashSupport, Actor, AnyRef, Any
Known Subclasses
AbstractActorWithStash, AbstractFSMWithStash, ActorClassificationUnsubscriber, PersistenceStash, PersistencePluginProxy
Type Hierarchy
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. Stash
  2. RequiresMessageQueue
  3. UnrestrictedStash
  4. StashSupport
  5. Actor
  6. AnyRef
  7. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Type Members

  1. type Receive = PartialFunction[Any, Unit]
    Definition Classes
    Actor

Abstract Value Members

  1. abstract def receive: Actor.Receive

    Scala API: This defines the initial actor behavior, it must return a partial function with the actor logic.

    Scala API: This defines the initial actor behavior, it must return a partial function with the actor logic.

    Definition Classes
    Actor

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from Stash toany2stringadd[Stash] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Stash, B)
    Implicit
    This member is added by an implicit conversion from Stash toArrowAssoc[Stash] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. def aroundPostRestart(reason: Throwable): Unit

    INTERNAL API.

    INTERNAL API.

    Can be overridden to intercept calls to postRestart. Calls postRestart by default.

    Attributes
    protected[pekko]
    Definition Classes
    Actor
    Annotations
    @InternalApi()
  7. def aroundPostStop(): Unit

    INTERNAL API.

    INTERNAL API.

    Can be overridden to intercept calls to postStop. Calls postStop by default.

    Attributes
    protected[pekko]
    Definition Classes
    Actor
    Annotations
    @InternalApi()
  8. def aroundPreRestart(reason: Throwable, message: Option[Any]): Unit

    INTERNAL API.

    INTERNAL API.

    Can be overridden to intercept calls to preRestart. Calls preRestart by default.

    Attributes
    protected[pekko]
    Definition Classes
    Actor
    Annotations
    @InternalApi()
  9. def aroundPreStart(): Unit

    INTERNAL API.

    INTERNAL API.

    Can be overridden to intercept calls to preStart. Calls preStart by default.

    Attributes
    protected[pekko]
    Definition Classes
    Actor
    Annotations
    @InternalApi()
  10. def aroundReceive(receive: Actor.Receive, msg: Any): Unit

    INTERNAL API.

    INTERNAL API.

    Can be overridden to intercept calls to this actor's current behavior.

    receive

    current behavior.

    msg

    current message.

    Attributes
    protected[pekko]
    Definition Classes
    Actor
    Annotations
    @InternalApi()
  11. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  12. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native() @HotSpotIntrinsicCandidate()
  13. implicit val context: ActorContext

    Scala API: Stores the context for this actor, including self, and sender.

    Scala API: Stores the context for this actor, including self, and sender. It is implicit to support operations such as forward.

    WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!

    pekko.actor.ActorContext is the Scala API. getContext returns a pekko.actor.AbstractActor.ActorContext, which is the Java API of the actor context.

    Definition Classes
    Actor
  14. def ensuring(cond: (Stash) => Boolean, msg: => Any): Stash
    Implicit
    This member is added by an implicit conversion from Stash toEnsuring[Stash] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  15. def ensuring(cond: (Stash) => Boolean): Stash
    Implicit
    This member is added by an implicit conversion from Stash toEnsuring[Stash] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  16. def ensuring(cond: Boolean, msg: => Any): Stash
    Implicit
    This member is added by an implicit conversion from Stash toEnsuring[Stash] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  17. def ensuring(cond: Boolean): Stash
    Implicit
    This member is added by an implicit conversion from Stash toEnsuring[Stash] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  18. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  19. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  20. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  21. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  22. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  23. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  24. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  25. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  26. def postRestart(reason: Throwable): Unit

    User overridable callback: By default it calls preStart().

    User overridable callback: By default it calls preStart().

    reason

    the Throwable that caused the restart to happen Is called right AFTER restart on the newly created Actor to allow reinitialization after an Actor crash.

    Definition Classes
    Actor
    Annotations
    @throws(classOf[Exception])
  27. def postStop(): Unit

    Overridden callback.

    Overridden callback. Prepends all messages in the stash to the mailbox and clears the stash. Must be called when overriding this method, otherwise stashed messages won't be propagated to DeadLetters when actor stops.

    Definition Classes
    UnrestrictedStash → Actor
    Annotations
    @throws(classOf[Exception])
  28. def preRestart(reason: Throwable, message: Option[Any]): Unit

    Overridden callback.

    Overridden callback. Prepends all messages in the stash to the mailbox, clears the stash, stops all children and invokes the postStop() callback.

    reason

    the Throwable that caused the restart to happen

    message

    optionally the current message the actor processed when failing, if applicable Is called on a crashed Actor right BEFORE it is restarted to allow clean up of resources before Actor is terminated.

    Definition Classes
    UnrestrictedStash → Actor
    Annotations
    @throws(classOf[Exception])
  29. def preStart(): Unit

    User overridable callback.

    User overridable callback.

    Is called when an Actor is started. Actors are automatically started asynchronously when created. Empty default implementation.

    Definition Classes
    Actor
    Annotations
    @throws(classOf[Exception])
  30. implicit final val self: ActorRef

    The 'self' field holds the ActorRef for this actor.

    The 'self' field holds the ActorRef for this actor.

    Can be used to send messages to itself: 

    self ! message

    Definition Classes
    Actor
  31. final def sender(): ActorRef

    The reference sender Actor of the last received message.

    The reference sender Actor of the last received message. Is defined if the message was sent from another Actor, else deadLetters in pekko.actor.ActorSystem.

    WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!

    Definition Classes
    Actor
  32. def stash(): Unit

    Adds the current message (the message that the actor received last) to the actor's stash.

    Adds the current message (the message that the actor received last) to the actor's stash.

    Definition Classes
    StashSupport
    Exceptions thrown

    IllegalStateException if the same message is stashed more than once

    StashOverflowException in case of a stash capacity violation

  33. def supervisorStrategy: SupervisorStrategy

    User overridable definition the strategy to use for supervising child actors.

    User overridable definition the strategy to use for supervising child actors.

    Definition Classes
    Actor
  34. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  35. def toString(): String
    Definition Classes
    AnyRef → Any
  36. def unhandled(message: Any): Unit

    User overridable callback.

    User overridable callback.

    Is called when a message isn't handled by the current behavior of the actor by default it fails with either a pekko.actor.DeathPactException (in case of an unhandled pekko.actor.Terminated message) or publishes an pekko.actor.UnhandledMessage to the actor's system's pekko.event.EventStream

    Definition Classes
    Actor
  37. def unstashAll(): Unit

    Prepends all messages in the stash to the mailbox, and then clears the stash.

    Prepends all messages in the stash to the mailbox, and then clears the stash.

    Messages from the stash are enqueued to the mailbox until the capacity of the mailbox (if any) has been reached. In case a bounded mailbox overflows, a MessageQueueAppendFailedException is thrown.

    The stash is guaranteed to be empty after calling unstashAll().

    Definition Classes
    StashSupport
  38. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  39. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  40. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])

Deprecated Value Members

  1. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable]) @Deprecated @Deprecated
    Deprecated
  2. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from Stash toStringFormat[Stash] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @deprecated @inline()
    Deprecated

    (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), or use the f"" string interpolator. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters.

  3. def →[B](y: B): (Stash, B)
    Implicit
    This member is added by an implicit conversion from Stash toArrowAssoc[Stash] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) Use -> instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

Inherited from RequiresMessageQueue[DequeBasedMessageQueueSemantics]

Inherited from UnrestrictedStash

Inherited from StashSupport

Inherited from Actor

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd fromStash to any2stringadd[Stash]

Inherited by implicit conversion StringFormat fromStash to StringFormat[Stash]

Inherited by implicit conversion Ensuring fromStash to Ensuring[Stash]

Inherited by implicit conversion ArrowAssoc fromStash to ArrowAssoc[Stash]

Ungrouped