Packages

abstract class ActorRef extends Comparable[ActorRef] with Serializable

Immutable and serializable handle to an actor, which may or may not reside on the local host or inside the same akka.actor.ActorSystem. An ActorRef can be obtained from an akka.actor.ActorRefFactory, an interface which is implemented by ActorSystem and akka.actor.ActorContext. This means actors can be created top-level in the ActorSystem or as children of an existing actor, but only from within that actor.

ActorRefs can be freely shared among actors by message passing. Message passing conversely is their only purpose, as demonstrated in the following examples:

Scala:

import akka.pattern.ask
import scala.concurrent.Await

class ExampleActor extends Actor {
  val other = context.actorOf(Props[OtherActor], "childName") // will be destroyed and re-created upon restart by default

  def receive {
    case Request1(msg) => other ! refine(msg)     // uses this actor as sender reference, reply goes to us
    case Request2(msg) => other.tell(msg, sender()) // forward sender reference, enabling direct reply
    case Request3(msg) =>
      implicit val timeout = Timeout(5.seconds)
      (other ? msg) pipeTo sender()
      // the ask call will get a future from other's reply
      // when the future is complete, send its value to the original sender
  }
}

Java:

import static akka.pattern.Patterns.ask;
import static akka.pattern.Patterns.pipe;

public class ExampleActor extends AbstractActor {
  // this child will be destroyed and re-created upon restart by default
  final ActorRef other = getContext().actorOf(Props.create(OtherActor.class), "childName");
  @Override
  public Receive createReceive() {
    return receiveBuilder()
      .match(Request1.class, msg ->
        // uses this actor as sender reference, reply goes to us
        other.tell(msg, getSelf()))
      .match(Request2.class, msg ->
        // forward sender reference, enabling direct reply
        other.tell(msg, getSender()))
      .match(Request3.class, msg ->
        // the ask call will get a future from other's reply
        // when the future is complete, send its value to the original sender
        pipe(ask(other, msg, 5000), context().dispatcher()).to(getSender()))
      .build();
  }
}

ActorRef does not have a method for terminating the actor it points to, use akka.actor.ActorRefFactory.stop(ref), or send a akka.actor.PoisonPill, for this purpose.

Two actor references are compared equal when they have the same path and point to the same actor incarnation. A reference pointing to a terminated actor doesn't compare equal to a reference pointing to another (re-created) actor with the same path.

If you need to keep track of actor references in a collection and do not care about the exact actor incarnation you can use the ActorPath as key because the unique id of the actor is not taken into account when comparing actor paths.

Self Type
InternalActorRef
Source
ActorRef.scala
Linear Supertypes
Serializable, Serializable, Comparable[ActorRef], AnyRef, Any
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Inherited
  1. ActorRef
  2. Serializable
  3. Serializable
  4. Comparable
  5. AnyRef
  6. Any
Implicitly
  1. by actorRef2Scala
  2. by any2stringadd
  3. by StringFormat
  4. by Ensuring
  5. by ArrowAssoc
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Visibility
  1. Public
  2. All

Instance Constructors

  1. new ActorRef()

Abstract Value Members

  1. abstract def path: ActorPath

    Returns the path for this actor (from this actor up to the root actor).

Concrete Value Members

  1. def !(message: Any)(implicit sender: ActorRef = Actor.noSender): Unit

    Sends a one-way asynchronous message.

    Sends a one-way asynchronous message. E.g. fire-and-forget semantics.

    If invoked from within an actor then the actor reference is implicitly passed on as the implicit 'sender' argument.

    This actor 'sender' reference is then available in the receiving actor in the 'sender()' member variable, if invoked from within an Actor. If not then no sender is available.

      actor ! message
    

    Implicit
    This member is added by an implicit conversion from ActorRef to ScalaActorRef performed by method actorRef2Scala in akka.actor.
    Definition Classes
    ScalaActorRef
  2. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  3. final def ##(): Int
    Definition Classes
    AnyRef → Any
  4. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from ActorRef to any2stringadd[ActorRef] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  5. def ->[B](y: B): (ActorRef, B)
    Implicit
    This member is added by an implicit conversion from ActorRef to ArrowAssoc[ActorRef] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  6. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  7. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  8. def clone(): AnyRef
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  9. final def compareTo(other: ActorRef): Int

    Comparison takes path and the unique id of the actor cell into account.

    Comparison takes path and the unique id of the actor cell into account.

    Definition Classes
    ActorRef → Comparable
  10. def ensuring(cond: (ActorRef) ⇒ Boolean, msg: ⇒ Any): ActorRef
    Implicit
    This member is added by an implicit conversion from ActorRef to Ensuring[ActorRef] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: (ActorRef) ⇒ Boolean): ActorRef
    Implicit
    This member is added by an implicit conversion from ActorRef to Ensuring[ActorRef] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: Boolean, msg: ⇒ Any): ActorRef
    Implicit
    This member is added by an implicit conversion from ActorRef to Ensuring[ActorRef] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. def ensuring(cond: Boolean): ActorRef
    Implicit
    This member is added by an implicit conversion from ActorRef to Ensuring[ActorRef] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  15. final def equals(that: Any): Boolean

    Equals takes path and the unique id of the actor cell into account.

    Equals takes path and the unique id of the actor cell into account.

    Definition Classes
    ActorRef → AnyRef → Any
  16. def finalize(): Unit
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  17. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from ActorRef to StringFormat[ActorRef] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  18. def forward(message: Any)(implicit context: ActorContext): Unit

    Forwards the message and passes the original sender actor as the sender.

    Forwards the message and passes the original sender actor as the sender.

    Works, no matter whether originally sent with tell/'!' or ask/'?'.

  19. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
  20. final def hashCode(): Int
    Definition Classes
    ActorRef → AnyRef → Any
  21. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  22. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  23. final def notify(): Unit
    Definition Classes
    AnyRef
  24. final def notifyAll(): Unit
    Definition Classes
    AnyRef
  25. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  26. final def tell(msg: Any, sender: ActorRef): Unit

    Sends the specified message to this ActorRef, i.e.

    Sends the specified message to this ActorRef, i.e. fire-and-forget semantics, including the sender reference if possible.

    Pass akka.actor.ActorRef noSender or null as sender if there is nobody to reply to

  27. def toString(): String
    Definition Classes
    ActorRef → AnyRef → Any
  28. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  29. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  30. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  31. def [B](y: B): (ActorRef, B)
    Implicit
    This member is added by an implicit conversion from ActorRef to ArrowAssoc[ActorRef] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Inherited from Serializable

Inherited from Serializable

Inherited from Comparable[ActorRef]

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion actorRef2Scala from ActorRef to ScalaActorRef

Inherited by implicit conversion any2stringadd from ActorRef to any2stringadd[ActorRef]

Inherited by implicit conversion StringFormat from ActorRef to StringFormat[ActorRef]

Inherited by implicit conversion Ensuring from ActorRef to Ensuring[ActorRef]

Inherited by implicit conversion ArrowAssoc from ActorRef to ArrowAssoc[ActorRef]

Ungrouped