akka.transactor

Transactor

trait Transactor extends Actor

An actor with built-in support for coordinated transactions.

Transactors implement the general pattern for using akka.stm.Coordinated where first any coordination messages are sent to other transactors, then the coordinated transaction is entered. Transactors can also accept explicitly sent Coordinated messages.

Simple transactors will just implement the atomically method which is similar to the actor receive method but runs within a coordinated transaction.

Example of a simple transactor that will join a coordinated transaction:

class Counter extends Transactor {
  val count = Ref(0)

  def atomically = {
    case Increment => count alter (_ + 1)
  }
}


To coordinate with other transactors override the coordinate method. The coordinate method maps a message to a set of akka.actor.Transactor.SendTo objects, pairs of ActorRef and a message. You can use the include and sendTo methods to easily coordinate with other transactors. The include method will send on the same message that was received to other transactors. The sendTo method allows you to specify both the actor to send to, and message to send.

Example of coordinating an increment:

class FriendlyCounter(friend: ActorRef) extends Transactor {
  val count = Ref(0)

  override def coordinate = {
    case Increment => include(friend)
  }

  def atomically = {
    case Increment => count alter (_ + 1)
  }
}


Using include to include more than one transactor:

override def coordinate = {
  case Message => include(actor1, actor2, actor3)
}


Using sendTo to coordinate transactions but send on a different message than the one that was received:

override def coordinate = {
  case Message => sendTo(someActor -> SomeOtherMessage)
  case SomeMessage => sendTo(actor1 -> Message1, actor2 -> Message2)
}


To execute directly before or after the coordinated transaction, override the before and after methods. These methods also expect partial functions like the receive method. They do not execute within the transaction.

To completely bypass coordinated transactions override the normally method. Any message matched by normally will not be matched by the other methods, and will not be involved in coordinated transactions. In this method you can implement normal actor behavior, or use the normal STM atomic for local transactions.

See also

akka.stm.Coordinated for more information about the underlying mechanism

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Type Members

  1. type Receive = PartialFunction[Any, Unit]

    Type alias because traits cannot have companion objects.

    Type alias because traits cannot have companion objects.

    Definition Classes
    Actor

Abstract Value Members

  1. def atomically : Receive

    The Receive block to run inside the coordinated transaction.

    The Receive block to run inside the coordinated transaction.

    Attributes
    abstract

Concrete Value Members

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

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

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

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

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

    Attributes
    final
    Definition Classes
    Any
  6. def after : Receive

    A Receive block that runs after the coordinated transaction.

  7. def alone : PartialFunction[Any, Set[SendTo]]

    Default coordination - no other transactors.

  8. def asInstanceOf [T0] : T0

    Attributes
    final
    Definition Classes
    Any
  9. def become (behavior: Receive, discardOld: Boolean = true): Unit

    Changes the Actor's behavior to become the new 'Receive' (PartialFunction[Any, Unit]) handler.

    Changes the Actor's behavior to become the new 'Receive' (PartialFunction[Any, Unit]) handler. Puts the behavior on top of the hotswap stack. If "discardOld" is true, an unbecome will be issued prior to pushing the new behavior to the stack

    Definition Classes
    Actor
  10. def before : Receive

    A Receive block that runs before the coordinated transaction is entered.

  11. def clone (): AnyRef

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
  12. def coordinate : PartialFunction[Any, Set[SendTo]]

    Override this method to coordinate with other transactors.

    Override this method to coordinate with other transactors. The other transactors are added to the coordinated transaction barrier and sent a Coordinated message. The message to send can be specified or otherwise the same message as received is sent. Use the 'include' and 'sendTo' methods to easily create the set of transactors to be involved.

  13. def doNothing : Receive

    Default catch-all for the different Receive methods.

  14. def eq (arg0: AnyRef): Boolean

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

    Definition Classes
    AnyRef → Any
  16. def finalize (): Unit

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
  17. def freshInstance (): Option[Actor]

    User overridable callback.

    User overridable callback.

    Is called on the crashed Actor to give it the option of producing the Actor's reincarnation. If it returns None, which is the default, the initially provided actor factory is used.

    Warning: Propagating state from a crashed actor carries the risk of proliferating the cause of the error. Consider let-it-crash first.

    Definition Classes
    Actor
    Annotations
    @experimental( since = "1.2" )
  18. def getClass (): java.lang.Class[_]

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

    Definition Classes
    AnyRef → Any
  20. def include (actors: ActorRef*): Set[SendTo]

    Include other actors in this coordinated transaction and send them the same message as received.

    Include other actors in this coordinated transaction and send them the same message as received. Use as the result in 'coordinated'.

  21. def isDefinedAt (message: Any): Boolean

    Is the actor able to handle the message passed in as arguments?

    Is the actor able to handle the message passed in as arguments?

    Definition Classes
    Actor
  22. def isInstanceOf [T0] : Boolean

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

    Attributes
    final
    Definition Classes
    AnyRef
  24. def nobody : Set[SendTo]

    Empty set of transactors to send to.

  25. def normally : Receive

    Bypass transactionality and behave like a normal actor.

  26. def notify (): Unit

    Attributes
    final
    Definition Classes
    AnyRef
  27. def notifyAll (): Unit

    Attributes
    final
    Definition Classes
    AnyRef
  28. def optionSelf : Option[ActorRef]

    Option[ActorRef] representation of the 'self' ActorRef reference.

    Option[ActorRef] representation of the 'self' ActorRef reference.

    Mainly for internal use, functions as the implicit sender references when invoking one of the message send functions ('!', '!!' and '!!!').

    Definition Classes
    Actor
  29. def postRestart (reason: Throwable): Unit

    User overridable callback.

    User overridable callback.

    Is called right AFTER restart on the newly created Actor to allow reinitialization after an Actor crash.

    Definition Classes
    Actor
  30. def postStop (): Unit

    User overridable callback.

    User overridable callback.

    Is called when 'actor.stop()' is invoked.

    Definition Classes
    Actor
  31. def preRestart (reason: Throwable, message: Option[Any]): Unit

    User overridable callback.

    User overridable callback.

    Is called on a crashed Actor right BEFORE it is restarted to allow clean up of resources before Actor is terminated. Override either the variant with or without the currentMessage argument.

    Definition Classes
    Actor
  32. def preStart (): Unit

    User overridable callback.

    User overridable callback.

    Is called when an Actor is started by invoking 'actor.start()'.

    Definition Classes
    Actor
  33. def receive : PartialFunction[Any, Unit]

    Implement a general pattern for using coordinated transactions.

    Implement a general pattern for using coordinated transactions.

    Attributes
    final
    Definition Classes
    TransactorActor
  34. implicit val self : ScalaActorRef

    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
    
    Here you also find most of the Actor API.

    For example fields like:

    self.dispatcher = ...
    self.trapExit = ...
    self.faultHandler = ...
    self.lifeCycle = ...
    self.sender
    

    Here you also find methods like:

    self.reply(..)
    self.link(..)
    self.unlink(..)
    self.start(..)
    self.stop(..)
    

    Attributes
    implicit
    Definition Classes
    Actor
  35. def sendTo (pairs: (ActorRef, Any)*): Set[SendTo]

    Include other actors in this coordinated transaction and specify the message to send by providing ActorRef -> Message pairs.

    Include other actors in this coordinated transaction and specify the message to send by providing ActorRef -> Message pairs. Use as the result in 'coordinated'.

  36. val someSelf : Some[ActorRef]

    Some[ActorRef] representation of the 'self' ActorRef reference.

    Some[ActorRef] representation of the 'self' ActorRef reference.

    Mainly for internal use, functions as the implicit sender references when invoking the 'forward' function.

    Definition Classes
    Actor
  37. def synchronized [T0] (arg0: ⇒ T0): T0

    Attributes
    final
    Definition Classes
    AnyRef
  38. def toString (): String

    Definition Classes
    AnyRef → Any
  39. def transactionFactory : TransactionFactory

    Create default transaction factory.

    Create default transaction factory. Override to provide custom configuration.

  40. def unbecome (): Unit

    Reverts the Actor behavior to the previous one in the hotswap stack.

    Reverts the Actor behavior to the previous one in the hotswap stack.

    Definition Classes
    Actor
  41. def unhandled (msg: 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 throws an UnhandledMessageException

    Definition Classes
    Actor
  42. def wait (): Unit

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

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

    Attributes
    final
    Definition Classes
    AnyRef
    Annotations
    @throws()

Deprecated Value Members

  1. def preRestart (reason: Throwable): Unit

    User overridable callback.

    User overridable callback.

    Is called on a crashed Actor right BEFORE it is restarted to allow clean up of resources before Actor is terminated. Override either the variant with or without the currentMessage argument.

    This method is deprecated: use the variant which receives the current message instead. This method will be removed in version 2.0.

    Definition Classes
    Actor
    Annotations
    @deprecated
    Deprecated

    use two-argument version, this one will be removed in 2.0

Inherited from Actor

Inherited from AnyRef

Inherited from Any