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
- Alphabetic
- By Inheritance
- Stash
- RequiresMessageQueue
- UnrestrictedStash
- StashSupport
- Actor
- AnyRef
- Any
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
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- Public
- Protected
Type Members
- type Receive = PartialFunction[Any, Unit]
- Definition Classes
- Actor
Abstract Value Members
- 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
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- final def ##: Int
- Definition Classes
- AnyRef → Any
- def +(other: String): String
- def ->[B](y: B): (Stash, B)
- final def ==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- def aroundPostRestart(reason: Throwable): Unit
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to
postRestart
. CallspostRestart
by default.- Attributes
- protected[pekko]
- Definition Classes
- Actor
- Annotations
- @InternalApi()
- def aroundPostStop(): Unit
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to
postStop
. CallspostStop
by default.- Attributes
- protected[pekko]
- Definition Classes
- Actor
- Annotations
- @InternalApi()
- def aroundPreRestart(reason: Throwable, message: Option[Any]): Unit
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to
preRestart
. CallspreRestart
by default.- Attributes
- protected[pekko]
- Definition Classes
- Actor
- Annotations
- @InternalApi()
- def aroundPreStart(): Unit
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to
preStart
. CallspreStart
by default.- Attributes
- protected[pekko]
- Definition Classes
- Actor
- Annotations
- @InternalApi()
- 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()
- final def asInstanceOf[T0]: T0
- Definition Classes
- Any
- def clone(): AnyRef
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.CloneNotSupportedException]) @HotSpotIntrinsicCandidate() @native()
- 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
- def ensuring(cond: (Stash) => Boolean, msg: => Any): Stash
- def ensuring(cond: (Stash) => Boolean): Stash
- def ensuring(cond: Boolean, msg: => Any): Stash
- def ensuring(cond: Boolean): Stash
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def equals(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef → Any
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- def hashCode(): Int
- Definition Classes
- AnyRef → Any
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- final def ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- final def notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- final def notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- 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])
- 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])
- 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])
- 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])
- 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
- 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
- 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
java.lang.IllegalStateException
if the same message is stashed more than oncepekko.actor.StashOverflowException
in case of a stash capacity violation
- 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
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
- def toString(): String
- Definition Classes
- AnyRef → Any
- 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
- 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
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException]) @native()
- final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
Deprecated Value Members
- def finalize(): Unit
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable]) @Deprecated
- Deprecated
(Since version 9)
- 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 ofvalue.formatted(formatString)
, or use thef""
string interpolator. In Java 15 and later,formatted
resolves to the new method in String which has reversed parameters.
- 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.