akka.transactor

Transactor

trait Transactor extends Actor

An actor with built-in support for coordinated transactions.

Transactors implement the general pattern for using Coordinated where 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 = implicit txn => {
    case Increment => count transform (_ + 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 = implicit txn => {
    case Increment => count transform (_ + 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

Coordinated for more information about the underlying mechanism

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Type Members

  1. type Receive = PartialFunction[Any, Unit]

    Definition Classes
    Actor

Abstract Value Members

  1. def atomically : (InTxn) ⇒ Receive

    The Receive block to run inside the coordinated transaction.

    The Receive block to run inside the coordinated transaction. This is a function from InTxn to Receive block.

    For example:

    def atomically = implicit txn => {
      case Increment => count transform (_ + 1)
    }
    
    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 before : Receive

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

  10. def clone (): AnyRef

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
  11. 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.

    Attributes
    protected[akka] implicit
    Definition Classes
    Actor
  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 getClass (): java.lang.Class[_]

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

    Definition Classes
    AnyRef → Any
  19. 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'.

  20. def isInstanceOf [T0] : Boolean

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

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

    Empty set of transactors to send to.

  23. def normally : Receive

    Bypass transactionality and behave like a normal actor.

  24. def notify (): Unit

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

    Attributes
    final
    Definition Classes
    AnyRef
  26. def postRestart (reason: Throwable): Unit

    User overridable callback: By default it calls preStart().

    User overridable callback: By default it calls preStart().

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

    Definition Classes
    Actor
  27. def postStop (): Unit

    User overridable callback.

    User overridable callback.

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

    Definition Classes
    Actor
  28. 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().

    Is called on a crashed Actor right BEFORE it is restarted to allow clean up of resources before Actor is terminated.

    Definition Classes
    Actor
  29. 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.

    Definition Classes
    Actor
  30. 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
  31. implicit 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
    

    Attributes
    implicit final
    Definition Classes
    Actor
  32. 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'.

  33. 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.

    Attributes
    final
    Definition Classes
    Actor
  34. def supervisorStrategy (): SupervisorStrategy

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

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

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

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

    Definition Classes
    AnyRef → Any
  37. 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

    Definition Classes
    Actor
  38. def wait (): Unit

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

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

    Attributes
    final
    Definition Classes
    AnyRef
    Annotations
    @throws()

Inherited from Actor

Inherited from AnyRef

Inherited from Any