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 ActorRef is available as self, the current message’s sender as sender and the 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).

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 ᅭcustomerᅮ
    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: Receive

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

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

    Attributes
    protected

Concrete Value Members

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

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

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  3. final def ##(): Int

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

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

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  6. final def asInstanceOf[T0]: T0

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  7. def clone(): AnyRef

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    protected[lang]
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    @throws()
  8. 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.

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

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    protected[akka]
  9. final def eq(arg0: AnyRef): Boolean

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  10. def equals(arg0: Any): Boolean

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  11. def finalize(): Unit

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  12. final def getClass(): java.lang.Class[_]

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  13. def hashCode(): Int

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  14. final def isInstanceOf[T0]: Boolean

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  15. final def ne(arg0: AnyRef): Boolean

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  16. final def notify(): Unit

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  17. final def notifyAll(): Unit

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  18. 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.

  19. def postStop(): Unit

    User overridable callback.

    User overridable callback.

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

  20. 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.

  21. 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.

  22. 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
    

  23. 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 ActorSystem.

  24. def supervisorStrategy(): SupervisorStrategy

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

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

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  26. def toString(): String

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  27. 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 DeathPactException (in case of an unhandled Terminated message) or publishes an UnhandledMessage to the actor's system's EventStream

  28. final def wait(): Unit

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

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  30. final def wait(arg0: Long): Unit

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