ActorRef

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

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)
      sender ! (other ? msg)  // will reply with a Future for holding other's reply
  }
}

Java:

import static akka.pattern.Patterns.ask;

public class ExampleActor Extends UntypedActor {
  // this child will be destroyed and re-created upon restart by default
  final ActorRef other = getContext().actorOf(Props.create(OtherActor.class), "childName");

  @Override
  public void onReceive(Object o) {
    if (o instanceof Request1) {
      Msg msg = ((Request1) o).getMsg();
      other.tell(msg, getSelf()); // uses this actor as sender reference, reply goes to us

    } else if (o instanceof Request2) {
      Msg msg = ((Request2) o).getMsg();
      other.tell(msg, getSender()); // forward sender reference, enabling direct reply

    } else if (o instanceof Request3) {
      Msg msg = ((Request3) o).getMsg();
      getSender().tell(ask(other, msg, 5000)); // reply with Future for holding the other's reply (timeout 5 seconds)

    } else {
      unhandled(o);
    }
  }
}

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. Actor references acquired with actorFor do not always include the full information about the underlying actor identity and therefore such references do not always compare equal to references acquired with actorOf, sender, or context.self.

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

Linear Supertypes

Serializable, Serializable, Comparable[ActorRef], AnyRef, Any

Known Subclasses

StandardOutLogger, TestActorRef, TestFSMRef

Type Hierarchy Learn more about scaladoc diagrams

Instance Constructors

new ActorRef()

Abstract Value Members

abstract def path: ActorPath

Returns the path for this actor (from this actor up to the root actor).
abstract def isTerminated: Boolean

Is the actor shut down? The contract is that if this method returns true, then it will never be false again.
Is the actor shut down? The contract is that if this method returns true, then it will never be false again. But you cannot rely on that it is alive if it returns false, since this by nature is a racy method.

Annotations
@deprecated
Deprecated
(Since version 2.2) Use context.watch(actor) and receive Terminated(actor)

Concrete Value Members

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 information
This member is added by an implicit conversion from ActorRef to ScalaActorRef performed by method actorRef2Scala in akka.actor.
Definition Classes
ScalaActorRef
final def !=(arg0: AnyRef): Boolean

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

Definition Classes
Any
final def ##(): Int

Definition Classes
AnyRef → Any
def +(other: String): String

Implicit information
This member is added by an implicit conversion from ActorRef to StringAdd performed by method any2stringadd in scala.Predef.
Definition Classes
StringAdd
def ->[B](y: B): (ActorRef, B)

Implicit information
This member is added by an implicit conversion from ActorRef to ArrowAssoc[ActorRef] performed by method any2ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()
final def ==(arg0: AnyRef): Boolean

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

Definition Classes
Any
final def asInstanceOf[T0]: T0

Definition Classes
Any
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
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
def ensuring(cond: (ActorRef) ⇒ Boolean, msg: ⇒ Any): ActorRef

Implicit information
This member is added by an implicit conversion from ActorRef to Ensuring[ActorRef] performed by method any2Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: (ActorRef) ⇒ Boolean): ActorRef

Implicit information
This member is added by an implicit conversion from ActorRef to Ensuring[ActorRef] performed by method any2Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: Boolean, msg: ⇒ Any): ActorRef

Implicit information
This member is added by an implicit conversion from ActorRef to Ensuring[ActorRef] performed by method any2Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: Boolean): ActorRef

Implicit information
This member is added by an implicit conversion from ActorRef to Ensuring[ActorRef] performed by method any2Ensuring in scala.Predef.
Definition Classes
Ensuring
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
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
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
def formatted(fmtstr: String): String

Implicit information
This member is added by an implicit conversion from ActorRef to StringFormat performed by method any2stringfmt in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()
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 with '!' and '?'/'ask'.
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
final def hashCode(): Int

Definition Classes
ActorRef → AnyRef → Any
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
final def tell(msg: Any, sender: ActorRef): Unit

Java API: Sends the specified message to the sender, i.
Java API: Sends the specified message to the sender, i.e. fire-and-forget semantics, including the sender reference if possible (pass null if there is nobody to reply to).
```
actor.tell(message, getSelf());
```
def toString(): String

Definition Classes
ActorRef → AnyRef → Any
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

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

Definition Classes
AnyRef
Annotations
@throws( ... )
def →[B](y: B): (ActorRef, B)

Implicit information
This member is added by an implicit conversion from ActorRef to ArrowAssoc[ActorRef] performed by method any2ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

Shadowed Implicit Value Members

val self: Any
Implicit information
This member is added by an implicit conversion from ActorRef to StringAdd performed by method any2stringadd in scala.Predef.
Shadowing
This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:
(actorRef: StringAdd).self
Definition Classes
StringAdd
val self: Any
Implicit information
This member is added by an implicit conversion from ActorRef to StringFormat performed by method any2stringfmt in scala.Predef.
Shadowing
This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:
(actorRef: StringFormat).self
Definition Classes
StringFormat

Deprecated Value Members

def x: ActorRef
Implicit information
This member is added by an implicit conversion from ActorRef to ArrowAssoc[ActorRef] performed by method any2ArrowAssoc in scala.Predef.
Shadowing
This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:
(actorRef: ArrowAssoc[ActorRef]).x
Definition Classes
ArrowAssoc
Annotations
@deprecated
Deprecated
(Since version 2.10.0) Use leftOfArrow instead
def x: ActorRef
Implicit information
This member is added by an implicit conversion from ActorRef to Ensuring[ActorRef] performed by method any2Ensuring in scala.Predef.
Shadowing
This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:
(actorRef: Ensuring[ActorRef]).x
Definition Classes
Ensuring
Annotations
@deprecated
Deprecated
(Since version 2.10.0) Use resultOfEnsuring instead

abstract class ActorRef extends Comparable[ActorRef] with Serializable

Instance Constructors

new ActorRef()

Abstract Value Members

abstract def path: ActorPath

abstract def isTerminated: Boolean

Concrete Value Members

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

final def !=(arg0: AnyRef): Boolean

final def !=(arg0: Any): Boolean

final def ##(): Int

def +(other: String): String

def ->[B](y: B): (ActorRef, B)

final def ==(arg0: AnyRef): Boolean

final def ==(arg0: Any): Boolean

final def asInstanceOf[T0]: T0

def clone(): AnyRef

final def compareTo(other: ActorRef): Int

def ensuring(cond: (ActorRef) ⇒ Boolean, msg: ⇒ Any): ActorRef

def ensuring(cond: (ActorRef) ⇒ Boolean): ActorRef

def ensuring(cond: Boolean, msg: ⇒ Any): ActorRef

def ensuring(cond: Boolean): ActorRef

final def eq(arg0: AnyRef): Boolean

final def equals(that: Any): Boolean

def finalize(): Unit

def formatted(fmtstr: String): String

def forward(message: Any)(implicit context: ActorContext): Unit

final def getClass(): Class[_]

final def hashCode(): Int

final def isInstanceOf[T0]: Boolean

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

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

final def tell(msg: Any, sender: ActorRef): Unit

def toString(): String

final def wait(): Unit

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

final def wait(arg0: Long): Unit

def →[B](y: B): (ActorRef, B)

Shadowed Implicit Value Members

val self: Any

val self: Any

Deprecated Value Members

def x: ActorRef

def x: ActorRef

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 StringAdd

Inherited by implicit conversion any2stringfmt from ActorRef to StringFormat

Inherited by implicit conversion any2ArrowAssoc from ActorRef to ArrowAssoc[ActorRef]

Inherited by implicit conversion any2Ensuring from ActorRef to Ensuring[ActorRef]

Ungrouped