All messages sent to the akka.actor.FSM will be wrapped inside an
Event
, which allows pattern matching to extract both state and data.
Case class representing the state of the akka.actor.FSM whithin the
onTermination
block.
This extractor is just convenience for matching a (S, S) pair, including a reminder what the new state is.
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.
This case object is received in case of a state timeout.
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
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
.
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.UntypedActorContext, 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.
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.
Chain this into the receive function.
Chain this into the receive function.
def receive = listenerManagement orElse
Return next state data (available in onTransition handlers)
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.
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()
.
Call onTermination
hook; if you want to retain this behavior when
overriding make sure to call super.postStop()
.
Please note that this method is called by default from preRestart()
,
so override that one if onTermination
shall not be called during
restart.
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()
.
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.
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.
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
current state descriptor
Set initial state.
Set initial state. Call this method from the constructor before the #initialize method.
initial state designator
initial state data
state timeout for the initial state, overriding the default timeout for that state
Return current state data (i.
Return current state data (i.e. object of type D)
Return current state name (i.
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.
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 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".
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.
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.
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
A akka.contrib.throttle.Throttler that uses a timer to control the message delivery rate.
Example
For example, if you set a rate like "3 messages in 1 second", the throttler will send the first three messages immediately to the target actor but will need to impose a delay before sending out further messages:
Implementation notes
This throttler implementation internally installs a timer that repeats every
rate.durationInMillis
and enablesrate.numberOfCalls
additional calls to take place. ATimerBasedThrottler
uses very few system resources, provided the rate's duration is not too fine-grained (which would cause a lot of timer invocations); for example, it does not store the calling history as other throttlers may need to do.However, a
TimerBasedThrottler
only provides weak guarantees on the rate (see also this blog post):rate.numberOfCalls
-many requests may be observed on the server in an interval of durationrate.durationInMillis()
.rate.durationInMillis()
that contain more thanrate.numberOfCalls
message deliveries: aTimerBasedThrottler
only makes guarantees for the intervals of its own timer, namely that no more thanrate.numberOfCalls
-many messages are delivered within such intervals. Other intervals on the timeline may contain more calls.For some applications, these guarantees may not be sufficient.
Known issues
SetRate(rate)
, the actual rate may in fact be higher for the overlapping period (i.e.,durationInMillis()
) of the new and old rate. Therefore, changing the rate frequently is not recommended with the current implementation.akka.contrib.throttle.Throttler