This extractor is just convenience for matching a (S, S) pair, including a reminder what the new state is.
This case object is received in case of a state timeout.
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to postRestart
. Calls postRestart
by default.
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to postStop
. Calls postStop
by default.
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to preRestart
. Calls preRestart
by default.
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to preStart
. Calls preStart
by default.
INTERNAL API.
INTERNAL API.
Can be overridden to intercept calls to this actor's current behavior.
current behavior.
current message.
Cancel named timer, ensuring that the message is not subsequently delivered (no race).
Cancel named timer, ensuring that the message is not subsequently delivered (no race).
of the timer to cancel
Scala API: Stores the context for this actor, including self, and sender.
Scala API: Stores the context for this actor, including self, and sender.
It is implicit to support operations such as forward
.
WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!
akka.actor.ActorContext is the Scala API. getContext
returns a
akka.actor.AbstractActor.ActorContext, which is the Java API of the actor
context.
Sends the supplied message to all current listeners using the provided sender() as sender.
Sends the supplied message to all current listeners using the provided sender() as sender.
Produce transition to other state.
Produce transition to other state. Return this from a state function in order to effect the transition.
This method always triggers transition events, even for A -> A
transitions.
If you want to stay in the same state without triggering an state transition event use #stay instead.
state designator for the next state
state transition descriptor
Verify existence of initial state and setup timers.
Verify existence of initial state and setup timers. This should be the last call within the constructor, or akka.actor.Actor#preStart and akka.actor.Actor#postRestart
An initial currentState -> currentState
notification will be triggered by calling this method.
Inquire whether the named timer is still active.
Inquire whether the named timer is still active. Returns true unless the timer does not exist, has previously been canceled or if it was a single-shot timer whose message was already received.
Chain this into the receive function.
Chain this into the receive function.
def receive = listenerManagement orElse …
By default FSM.Failure is logged at error level and other reason types are not logged.
By default FSM.Failure is logged at error level and other reason types are not logged. It is possible to override this behavior.
Return next state data (available in onTransition handlers)
Set handler which is called upon termination of this FSM actor.
Set handler which is called upon termination of this FSM actor. Calling this method again will overwrite the previous contents.
Set handler which is called upon each state transition, i.e.
Set handler which is called upon each state transition, i.e. not when staying in the same state. This may use the pair extractor defined in the FSM companion object like so:
onTransition { case Old -> New => doSomething }
It is also possible to supply a 2-ary function object:
onTransition(handler _) private def handler(from: S, to: S) { ... }
The underscore is unfortunately necessary to enable the nicer syntax shown above (it uses the implicit conversion total2pf under the hood).
Multiple handlers may be installed, and every one of them will be called, not only the first one matching.
User overridable callback: By default it calls preStart()
.
User overridable callback: By default it calls preStart()
.
the Throwable that caused the restart to happen Is called right AFTER restart on the newly created Actor to allow reinitialization after an Actor crash.
Call onTermination
hook; if you want to retain this behavior when
overriding make sure to call super.postStop()
.
Scala API: User overridable callback: By default it disposes of all children and then calls postStop()
.
Scala API: User overridable callback: By default it disposes of all children and then calls postStop()
.
the Throwable that caused the restart to happen
optionally the current message the actor processed when failing, if applicable Is called on a crashed Actor right BEFORE it is restarted to allow clean up of resources before Actor is terminated.
User overridable callback.
User overridable callback.
Is called when an Actor is started. Actors are automatically started asynchronously when created. Empty default implementation.
Scala API: This defines the initial actor behavior, it must return a partial function with the actor logic.
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
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 akka.actor.ActorSystem.
WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!
Set state timeout explicitly.
Set state timeout explicitly. This method can safely be used from within a state handler.
Schedule named timer to deliver message after given delay, possibly repeating.
Schedule named timer to deliver message after given delay, possibly repeating. Any existing timer with the same name will automatically be canceled before adding the new timer.
identifier to be used with cancelTimer()
message to be delivered
delay of first message delivery and between subsequent messages
send once if false, scheduleAtFixedRate if true
Set initial state.
Set initial state. Call this method from the constructor before the #initialize method. If different state is needed after a restart this method, followed by #initialize, can be used in the actor life cycle hooks akka.actor.Actor#preStart and akka.actor.Actor#postRestart.
initial state designator
initial state data
state timeout for the initial state, overriding the default timeout for that state
Return current state data (i.e.
Return current state data (i.e. object of type D)
Return current state name (i.e.
Return current state name (i.e. object of type S)
Produce "empty" transition descriptor.
Produce "empty" transition descriptor. Return this from a state function when no state change is to be effected.
No transition event will be triggered by #stay.
If you want to trigger an event like S -> S
for onTransition
to handle use goto
instead.
descriptor for staying in current state
Produce change descriptor to stop this FSM actor including specified reason.
Produce change descriptor to stop this FSM actor including specified reason.
Produce change descriptor to stop this FSM actor with reason "Normal".
User overridable definition the strategy to use for supervising child actors.
User overridable definition the strategy to use for supervising child actors.
Convenience wrapper for using a total function instead of a partial function literal.
Convenience wrapper for using a total function instead of a partial function literal. To be used with onTransition.
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 akka.actor.DeathPactException (in case of an unhandled akka.actor.Terminated message) or publishes an akka.actor.UnhandledMessage to the actor's system's akka.event.EventStream
Insert a new StateFunction at the end of the processing chain for the given state.
Insert a new StateFunction at the end of the processing chain for the given state. If the stateTimeout parameter is set, entering this state without a differing explicit timeout setting will trigger a StateTimeout event; the same is true when using #stay.
designator for the state
default state timeout for this state
partial function describing response to input
Set handler which is called upon reception of unhandled messages.
Set handler which is called upon reception of unhandled messages. Calling this method again will overwrite the previous contents.
The current state may be queried using
.
stateName
(fSM: ArrowAssoc[FSM[S, D]]).->(y)
Finite State Machine actor trait. Use as follows:
Within the partial function the following values are returned for effecting state transitions:
stay
for staying in the same statestay using Data(...)
for staying in the same state, but with different datastay forMax 5.millis
for staying with a state timeout; can be combined withusing
goto(...)
for changing into a different state; also supportsusing
andforMax
stop
for terminating this FSM actorEach of the above also supports the method
replying(AnyRef)
for sending a reply before changing state.While changing state, custom handlers may be invoked which are registered using
onTransition
. This is meant to enable concentrating different concerns in different places; you may choose to usewhen
for describing the properties of a state, including of course initiating transitions, but you can describe the transitions usingonTransition
to avoid having to duplicate that code among multiple paths which lead to a transition:Multiple such blocks are supported and all of them will be called, not only the first matching one.
Another feature is that other actors may subscribe for transition events by sending a
SubscribeTransitionCallback
message to this actor. Stopping a listener without unregistering will not remove the listener from the subscription list; useUnsubscribeTransitionCallback
before stopping the listener.State timeouts set an upper bound to the time which may pass before another message is received in the current state. If no external message is available, then upon expiry of the timeout a StateTimeout message is sent. Note that this message will only be received in the state for which the timeout was set and that any message received will cancel the timeout (possibly to be started again by the next transition).
Another feature is the ability to install and cancel single-shot as well as repeated timers which arrange for the sending of a user-specified message: