akka.actor

Actor

trait Actor extends AnyRef

Actor base trait that should be extended by or mixed to create an Actor with the semantics of the 'Actor Model': http://en.wikipedia.org/wiki/Actor_model

An actor has a well-defined (non-cyclic) life-cycle.

The Actor's own akka.actor.ActorRef is available as self, the current message’s sender as sender() and the akka.actor.ActorContext as context. The only abstract method is receive which shall return the initial behavior of the actor as a partial function (behavior can be changed using context.become and context.unbecome).

This is the Scala API (hence the Scala code below), for the Java API see akka.actor.UntypedActor.

class ExampleActor extends Actor {

override val supervisorStrategy = OneForOneStrategy(maxNrOfRetries = 10, withinTimeRange = 1 minute) {
  case _: ArithmeticException      => Resume
  case _: NullPointerException     => Restart
  case _: IllegalArgumentException => Stop
  case _: Exception                => Escalate
}

def receive = {
                                   // directly calculated reply
  case Request(r)               => sender() ! calculate(r)

                                   // just to demonstrate how to stop yourself
  case Shutdown                 => context.stop(self)

                                   // error kernel with child replying directly to 'sender()'
  case Dangerous(r)             => context.actorOf(Props[ReplyToOriginWorker]).tell(PerformWork(r), sender())

                                   // error kernel with reply going through us
  case OtherJob(r)              => context.actorOf(Props[ReplyToMeWorker]) ! JobRequest(r, sender())
  case JobReply(result, orig_s) => orig_s ! result
}
}

The last line demonstrates the essence of the error kernel design: spawn one-off actors which terminate after doing their job, pass on sender() to allow direct reply if that is what makes sense, or round-trip the sender as shown with the fictitious JobRequest/JobReply message pair.

If you don’t like writing context you can always import context._ to get direct access to actorOf, stop etc. This is not default in order to keep the name-space clean.

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Type Members

  1. type Receive = PartialFunction[Any, Unit]

Abstract Value Members

  1. abstract def receive: Actor.Receive

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

Concrete Value Members

  1. final def !=(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  2. final def !=(arg0: Any): Boolean

    Definition Classes
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  3. final def ##(): Int

    Definition Classes
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  4. final def ==(arg0: AnyRef): Boolean

    Definition Classes
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  5. final def ==(arg0: Any): Boolean

    Definition Classes
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  6. def aroundPostRestart(reason: Throwable): Unit

    Can be overridden to intercept calls to postRestart.

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

    Attributes
    protected[akka]
  7. def aroundPostStop(): Unit

    Can be overridden to intercept calls to postStop.

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

    Attributes
    protected[akka]
  8. def aroundPreRestart(reason: Throwable, message: Option[Any]): Unit

    Can be overridden to intercept calls to preRestart.

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

    Attributes
    protected[akka]
  9. def aroundPreStart(): Unit

    Can be overridden to intercept calls to preStart.

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

    Attributes
    protected[akka]
  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[akka]
  11. final def asInstanceOf[T0]: T0

    Definition Classes
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  12. def clone(): AnyRef

    Attributes
    protected[java.lang]
    Definition Classes
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    @HotSpotIntrinsicCandidate() @throws( ... )
  13. implicit val context: ActorContext

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

    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!

    akka.actor.ActorContext is the Scala API. getContext returns a akka.actor.UntypedActorContext, which is the Java API of the actor context.

  14. final def eq(arg0: AnyRef): Boolean

    Definition Classes
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  15. def equals(arg0: Any): Boolean

    Definition Classes
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  16. final def getClass(): Class[_]

    Definition Classes
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    @HotSpotIntrinsicCandidate()
  17. def hashCode(): Int

    Definition Classes
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    Annotations
    @HotSpotIntrinsicCandidate()
  18. final def isInstanceOf[T0]: Boolean

    Definition Classes
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  19. final def ne(arg0: AnyRef): Boolean

    Definition Classes
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  20. final def notify(): Unit

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    @HotSpotIntrinsicCandidate()
  21. final def notifyAll(): Unit

    Definition Classes
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    @HotSpotIntrinsicCandidate()
  22. 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.

    Annotations
    @throws( classOf[Exception] )
  23. def postStop(): Unit

    User overridable callback.

    User overridable callback.

    Is called asynchronously after 'actor.stop()' is invoked. Empty default implementation.

    Annotations
    @throws( classOf[Exception] )
  24. def preRestart(reason: Throwable, message: Option[Any]): Unit

    User overridable callback: By default it disposes of all children and then calls postStop().

    User overridable callback: By default it disposes of all children and then calls postStop().

    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.

    Annotations
    @throws( classOf[Exception] )
  25. 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.

    Annotations
    @throws( classOf[Exception] )
  26. 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
    

  27. 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 akka.actor.ActorSystem.

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

  28. def supervisorStrategy: SupervisorStrategy

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

  29. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef
  30. def toString(): String

    Definition Classes
    AnyRef → Any
  31. 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 akka.actor.DeathPactException (in case of an unhandled akka.actor.Terminated message) or publishes an akka.actor.UnhandledMessage to the actor's system's akka.event.EventStream

  32. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
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    @throws( ... )
  33. final def wait(arg0: Long): Unit

    Definition Classes
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    @throws( ... )
  34. final def wait(): Unit

    Definition Classes
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    @throws( ... )

Deprecated Value Members

  1. def finalize(): Unit

    Attributes
    protected[java.lang]
    Definition Classes
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    Annotations
    @Deprecated @deprecated @throws( classOf[java.lang.Throwable] )
    Deprecated

    (Since version ) see corresponding Javadoc for more information.

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