scala.actors

Actor

trait Actor extends AbstractActor with ReplyReactor with ActorCanReply with InputChannel[Any] with Serializable

Provides lightweight, concurrent actors. Actors are created by extending the Actor trait (alternatively, one of the factory methods in its companion object can be used). The behavior of an Actor subclass is defined by implementing its act method:

  class MyActor extends Actor {
    def act() {
      // actor behavior goes here
    }
  }

A new Actor instance is started by invoking its start method.

Note: care must be taken when invoking thread-blocking methods other than those provided by the Actor trait or its companion object (such as receive). Blocking the underlying thread inside an actor may lead to starvation of other actors. This also applies to actors hogging their thread for a long time between invoking receive/react.

If actors use blocking operations (for example, methods for blocking I/O), there are several options:

The main ideas of the implementation are explained in the two papers

- Event-Based Programming without Inversion of Control, Philipp Haller and Martin Odersky, Proc. JMLC 2006, and

- Actors that Unify Threads and Events, Philipp Haller and Martin Odersky, Proc. COORDINATION 2007.

Annotations
@SerialVersionUID( uid = 781154067877019505L )
Source
Actor.scala
Linear Supertypes
Serializable, Serializable, InputChannel[Any], ActorCanReply, ReplyReactor, ReactorCanReply, Reactor[Any], Combinators, AbstractActor, CanReply[Any, Any], OutputChannel[Any], AnyRef, Any
Known Subclasses
Ordering
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Inherited
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  1. Actor
  2. Serializable
  3. Serializable
  4. InputChannel
  5. ActorCanReply
  6. ReplyReactor
  7. ReactorCanReply
  8. Reactor
  9. Combinators
  10. AbstractActor
  11. CanReply
  12. OutputChannel
  13. AnyRef
  14. Any
Visibility
  1. Public
  2. All

Type Members

  1. type Future[+P] = Future[P]

    Definition Classes
    ReactorCanReply → CanReply

Abstract Value Members

  1. abstract def act(): Unit

    The actor's behavior is specified by implementing this method.

    The actor's behavior is specified by implementing this method.

    Definition Classes
    Reactor

Concrete Value Members

  1. def !(msg: Any): Unit

    Sends msg to this actor (asynchronous).

    Sends msg to this actor (asynchronous).

    msg

    the message to send

    Definition Classes
    ReplyReactorReactorOutputChannel
  2. def !!(msg: Any): Future[Any]

    Sends msg to this actor and immediately returns a future representing the reply value.

    Sends msg to this actor and immediately returns a future representing the reply value.

    msg

    the message to be sent

    returns

    the future

    Definition Classes
    ActorCanReply → ReactorCanReply → CanReply
  3. def !![A](msg: Any, handler: PartialFunction[Any, A]): Future[A]

    Sends msg to this actor and immediately returns a future representing the reply value.

    Sends msg to this actor and immediately returns a future representing the reply value. The reply is post-processed using the partial function handler. This also allows to recover a more precise type for the reply value.

    msg

    the message to be sent

    handler

    the function to be applied to the response

    returns

    the future

    Definition Classes
    ActorCanReply → ReactorCanReply → CanReply
  4. final def !=(arg0: AnyRef): Boolean

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

    Test two objects for inequality.

    Test two objects for inequality.

    returns

    true if !(this == that), false otherwise.

    Definition Classes
    Any
  6. def !?(msec: Long, msg: Any): Option[Any]

    Sends msg to this actor and awaits reply (synchronous) within msec milliseconds.

    Sends msg to this actor and awaits reply (synchronous) within msec milliseconds.

    msec

    the time span before timeout

    msg

    the message to be sent

    returns

    None in case of timeout, otherwise Some(x) where x is the reply

    Definition Classes
    ActorCanReply → ReactorCanReply → CanReply
  7. def !?(msg: Any): Any

    Sends msg to this actor and awaits reply (synchronous).

    Sends msg to this actor and awaits reply (synchronous).

    msg

    the message to be sent

    returns

    the reply

    Definition Classes
    ActorCanReply → ReactorCanReply → CanReply
  8. final def ##(): Int

    Equivalent to x.hashCode except for boxed numeric types.

    Equivalent to x.hashCode except for boxed numeric types. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them.

    returns

    a hash value consistent with ==

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

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

    Test two objects for equality.

    Test two objects for equality.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    Any
  11. def ?: Any

    Receives the next message from the mailbox

    Receives the next message from the mailbox

    Definition Classes
    ActorInputChannel
  12. final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type T0.

    Cast the receiver object to be of type T0.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown
    ClassCastException

    if the receiver object is not an instance of the erasure of type T0.

  13. def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
    Note

    not specified by SLS as a member of AnyRef

  14. def continue(): Unit

    Continues with the execution of the closure registered as continuation following andThen.

    Continues with the execution of the closure registered as continuation following andThen. Continues with the execution of the next loop iteration when invoked inside the body of loop or loopWhile.

    Definition Classes
    Combinators
  15. final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (arg0) is a reference to the receiver object (this).

    Tests whether the argument (arg0) is a reference to the receiver object (this).

    The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:

    • It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.
    • For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false.
    • null.eq(null) returns true.

    When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

    returns

    true if the argument is a reference to the receiver object; false otherwise.

    Definition Classes
    AnyRef
  16. def equals(arg0: Any): Boolean

    The equality method for reference types.

    The equality method for reference types. See equals in Any.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    AnyRef → Any
  17. def exceptionHandler: PartialFunction[Exception, Unit]

    This partial function is applied to exceptions that propagate out of this actor's body.

    This partial function is applied to exceptions that propagate out of this actor's body.

    Attributes
    protected[actors]
    Definition Classes
    Reactor
  18. def exit(): Nothing

    Terminates with exit reason 'normal.

    Terminates with exit reason 'normal.

    Attributes
    protected[actors]
    Definition Classes
    ActorReactor
  19. def exit(reason: AnyRef): Nothing

    Terminates execution of self with the following effect on linked actors:

    Terminates execution of self with the following effect on linked actors:

    For each linked actor a with trapExit set to true, send message Exit(self, reason) to a.

    For each linked actor a with trapExit set to false (default), call a.exit(reason) if reason != 'normal.

    Attributes
    protected[actors]
  20. def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
    Note

    not specified by SLS as a member of AnyRef

  21. def forward(msg: Any): Unit

    Forwards msg to this actor (asynchronous).

    Forwards msg to this actor (asynchronous).

    msg

    the message to forward

    Definition Classes
    ReplyReactorReactorOutputChannel
  22. final def getClass(): java.lang.Class[_]

    A representation that corresponds to the dynamic class of the receiver object.

    A representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

    a representation that corresponds to the dynamic class of the receiver object.

    Definition Classes
    AnyRef → Any
    Note

    not specified by SLS as a member of AnyRef

  23. def getState: Value

    State of this actor

    State of this actor

    returns

    the execution state

    Definition Classes
    ActorReplyReactorReactor
  24. def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in Any.

    returns

    the hash code value for this object.

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

    Test whether the dynamic type of the receiver object is T0.

    Test whether the dynamic type of the receiver object is T0.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

    Definition Classes
    Any
  26. def link(body: ⇒ Unit): Actor

    Links self to the actor defined by body.

    Links self to the actor defined by body.

    body

    the body of the actor to link to

    returns

    the parameter actor

  27. def link(to: AbstractActor): AbstractActor

    Links self to actor to.

    Links self to actor to.

    to

    the actor to link to

    returns

    the parameter actor

  28. def loop(body: ⇒ Unit): Unit

    Repeatedly executes body.

    Repeatedly executes body.

    body

    the block to be executed

    Definition Classes
    Combinators
  29. def loopWhile(cond: ⇒ Boolean)(body: ⇒ Unit): Unit

    Repeatedly executes body while the condition cond is true.

    Repeatedly executes body while the condition cond is true.

    cond

    the condition to test

    body

    the block to be executed

    Definition Classes
    Combinators
  30. def mailboxSize: Int

    Attributes
    protected[actors]
    Definition Classes
    Reactor
  31. implicit def mkBody[A](body: ⇒ A): Body[A]

    Enables the composition of suspendable closures using andThen, loop, loopWhile, etc.

    Enables the composition of suspendable closures using andThen, loop, loopWhile, etc.

    Definition Classes
    Reactor → Combinators
  32. final def ne(arg0: AnyRef): Boolean

    Equivalent to !(this eq that).

    Equivalent to !(this eq that).

    returns

    true if the argument is not a reference to the receiver object; false otherwise.

    Definition Classes
    AnyRef
  33. final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Note

    not specified by SLS as a member of AnyRef

  34. final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Note

    not specified by SLS as a member of AnyRef

  35. def react(handler: PartialFunction[Any, Unit]): Nothing

    See the companion object's react method.

    See the companion object's react method.

    Definition Classes
    ActorInputChannelReplyReactorReactor
  36. def reactWithin(msec: Long)(handler: PartialFunction[Any, Unit]): Nothing

    See the companion object's reactWithin method.

    See the companion object's reactWithin method.

    msec

    the time span before timeout

    Definition Classes
    ActorInputChannelReplyReactor
  37. def receive[R](f: PartialFunction[Any, R]): R

    See the companion object's receive method.

    See the companion object's receive method.

    f

    a partial function with message patterns and actions

    returns

    result of processing the received value

    Definition Classes
    ActorInputChannel
  38. def receiveWithin[R](msec: Long)(f: PartialFunction[Any, R]): R

    See the companion object's receiveWithin method.

    See the companion object's receiveWithin method.

    msec

    the time span before timeout

    f

    a partial function with message patterns and actions

    returns

    result of processing the received value

    Definition Classes
    ActorInputChannel
  39. def receiver: Actor

    Returns the Actor that is receiving from this actor.

    Returns the Actor that is receiving from this actor.

    Definition Classes
    ReactorOutputChannel
  40. def reply(msg: Any): Unit

    Replies with msg to the sender.

    Replies with msg to the sender.

    Attributes
    protected[actors]
    Definition Classes
    ReplyReactor
  41. def restart(): Unit

    Restarts this actor.

    Restarts this actor.

    Definition Classes
    Reactor
    Exceptions thrown
    java.lang.IllegalStateException

    if the actor is not in state Actor.State.Terminated

  42. def scheduler: IScheduler

    Attributes
    protected[actors]
    Definition Classes
    ActorReactor
  43. def send(msg: Any, replyTo: OutputChannel[Any]): Unit

    Sends msg to this actor (asynchronous) supplying explicit reply destination.

    Sends msg to this actor (asynchronous) supplying explicit reply destination.

    msg

    the message to send

    replyTo

    the reply destination

    Definition Classes
    ReactorOutputChannel
  44. def sender: OutputChannel[Any]

    Returns the actor which sent the last received message.

    Returns the actor which sent the last received message.

    Attributes
    protected[actors]
    Definition Classes
    ReplyReactor
  45. def start(): Actor

    Starts this actor.

    Starts this actor. This method is idempotent.

    Definition Classes
    ActorReactor
  46. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef
  47. def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

    a String representation of the object.

    Definition Classes
    AnyRef → Any
  48. var trapExit: Boolean

  49. def unlink(from: AbstractActor): Unit

    Unlinks self from actor from.

  50. final def wait(): Unit

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

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

    Definition Classes
    AnyRef
    Annotations
    @throws()

Inherited from Serializable

Inherited from Serializable

Inherited from InputChannel[Any]

Inherited from ActorCanReply

Inherited from ReplyReactor

Inherited from ReactorCanReply

Inherited from Reactor[Any]

Inherited from Combinators

Inherited from AbstractActor

Inherited from CanReply[Any, Any]

Inherited from OutputChannel[Any]

Inherited from AnyRef

Inherited from Any