PersistentFSMBase
Finite State Machine actor trait. Use as follows:
object A {
trait State
case class One extends State
case class Two extends State
case class Data(i : Int)
}
class A extends Actor with FSM[A.State, A.Data] {
import A._
startWith(One, Data(42))
when(One) {
case Event(SomeMsg, Data(x)) => ...
case Event(SomeOtherMsg, _) => ... // convenience when data not needed
}
when(Two, stateTimeout = 5 seconds) { ... }
initialize()
}
Within the partial function the following values are returned for effecting state transitions:
stayfor staying in the same statestay using Data(...)for staying in the same state, but with different datastay forMax 5.millisfor staying with a state timeout; can be combined withusinggoto(...)for changing into a different state; also supportsusingandforMaxstopfor terminating this FSM actor
Each 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 use
when for describing the properties of a state, including of
course initiating transitions, but you can describe the transitions using
onTransition to avoid having to duplicate that code among
multiple paths which lead to a transition:
onTransition {
case Active -> _ => cancelTimer("activeTimer")
}
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; use UnsubscribeTransitionCallback 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:
startTimerWithFixedDelay("tock", TockMsg, 1 second) // repeating
startSingleTimer("lifetime", TerminateMsg, 1 hour) // single-shot
cancelTimer("tock")
isTimerActive("tock")
- Deprecated
- Source:
- PersistentFSMBase.scala
Type members
Classlikes
Types
Inherited types
Value members
Concrete methods
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).
- Value parameters:
- name
of the timer to cancel
- Source:
- PersistentFSMBase.scala
Produce transition to other state. Return this from a state function in order to effect the transition.
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.
- Value parameters:
- nextStateName
state designator for the next state
- Returns:
state transition descriptor
- Source:
- PersistentFSMBase.scala
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.
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.
- Source:
- PersistentFSMBase.scala
By default PersistentFSM.Failure is logged at error level and other reason types are not logged. It is possible to override this behavior.
By default PersistentFSM.Failure is logged at error level and other reason types are not logged. It is possible to override this behavior.
- Source:
- PersistentFSMBase.scala
Return next state data (available in onTransition handlers)
Return next state data (available in onTransition handlers)
- Source:
- PersistentFSMBase.scala
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 termination of this FSM actor. Calling this method again will overwrite the previous contents.
- Source:
- PersistentFSMBase.scala
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:
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.
- Source:
- PersistentFSMBase.scala
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.
- Definition Classes
- Source:
- PersistentFSMBase.scala
Set state timeout explicitly. This method can safely be used from within a state handler.
Set state timeout explicitly. This method can safely be used from within a state handler.
- Source:
- PersistentFSMBase.scala
Start a timer that will send msg once to the self actor after
the given delay.
Start a timer that will send msg once to the self actor after
the given delay.
Each timer has a name and if a new timer with same name is started
the previous is cancelled. It is guaranteed that a message from the
previous timer is not received, even if it was already enqueued
in the mailbox when the new timer was started.
- Source:
- PersistentFSMBase.scala
Schedules a message to be sent repeatedly to the self actor with a
given frequency.
Schedules a message to be sent repeatedly to the self actor with a
given frequency.
It will compensate the delay for a subsequent message if the sending of previous message was delayed more than specified. In such cases, the actual message interval will differ from the interval passed to the method.
If the execution is delayed longer than the interval, the subsequent message will
be sent immediately after the prior one. This also has the consequence that after
long garbage collection pauses or other reasons when the JVM was suspended all
"missed" messages will be sent when the process wakes up again.
In the long run, the frequency of messages will be exactly the reciprocal of the
specified interval.
Warning: startTimerAtFixedRate can result in bursts of scheduled messages after long
garbage collection pauses, which may in worst case cause undesired load on the system.
Therefore startTimerWithFixedDelay is often preferred.
Each timer has a name and if a new timer with same name is started
the previous is cancelled. It is guaranteed that a message from the
previous timer is not received, even if it was already enqueued
in the mailbox when the new timer was started.
- Source:
- PersistentFSMBase.scala
Schedules a message to be sent repeatedly to the self actor with a
fixed delay between messages.
Schedules a message to be sent repeatedly to the self actor with a
fixed delay between messages.
It will not compensate the delay between messages if scheduling is delayed
longer than specified for some reason. The delay between sending of subsequent
messages will always be (at least) the given delay.
In the long run, the frequency of messages will generally be slightly lower than
the reciprocal of the specified delay.
Each timer has a name and if a new timer with same name is started
the previous is cancelled. It is guaranteed that a message from the
previous timer is not received, even if it was already enqueued
in the mailbox when the new timer was started.
- Source:
- PersistentFSMBase.scala
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.
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.
- Value parameters:
- stateData
initial state data
- stateName
initial state designator
- timeout
state timeout for the initial state, overriding the default timeout for that state
- Source:
- PersistentFSMBase.scala
Return current state data (i.e. object of type D)
Return current state data (i.e. object of type D)
- Source:
- PersistentFSMBase.scala
Return current state name (i.e. object of type S)
Return current state name (i.e. object of type S)
- Source:
- PersistentFSMBase.scala
Produce "empty" transition descriptor. Return this from a state function when no state change is to be effected.
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.
- Returns:
descriptor for staying in current state
- Source:
- PersistentFSMBase.scala
Produce change descriptor to stop this FSM actor with reason "Normal".
Produce change descriptor to stop this FSM actor with reason "Normal".
- Source:
- PersistentFSMBase.scala
Produce change descriptor to stop this FSM actor including specified reason.
Produce change descriptor to stop this FSM actor including specified reason.
- Source:
- PersistentFSMBase.scala
Produce change descriptor to stop this FSM actor including specified reason.
Produce change descriptor to stop this FSM actor including specified reason.
- Source:
- PersistentFSMBase.scala
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.
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.
- Value parameters:
- stateFunction
partial function describing response to input
- stateName
designator for the state
- stateTimeout
default state timeout for this state
- Source:
- PersistentFSMBase.scala
Set handler which is called upon reception of unhandled messages. Calling this method again will overwrite the previous contents.
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.
- Source:
- PersistentFSMBase.scala
Deprecated methods
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.
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.
- Value parameters:
- msg
message to be delivered
- name
identifier to be used with cancelTimer()
- repeat
send once if false, scheduleAtFixedRate if true
- timeout
delay of first message delivery and between subsequent messages
- Deprecated
[Since version 2.6.0]- Source:
- PersistentFSMBase.scala
Inherited methods
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.
- Inherited from:
- Listeners
- Source:
- Listeners.scala
Chain this into the receive function.
Chain this into the receive function.
def receive = listenerManagement orElse …
- Inherited from:
- Listeners
- Source:
- Listeners.scala
User overridable callback: By default it calls preStart().
User overridable callback: By default it calls preStart().
- Value parameters:
- reason
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.
- Inherited from:
- Actor
- Source:
- Actor.scala
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().'''
- Value parameters:
- message
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.
- reason
the Throwable that caused the restart to happen
- Inherited from:
- Actor
- Source:
- Actor.scala
User overridable callback.
User overridable callback.
Is called when an Actor is started. Actors are automatically started asynchronously when created. Empty default implementation.
- Inherited from:
- Actor
- Source:
- Actor.scala
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.
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!
- Inherited from:
- Actor
- Source:
- Actor.scala
User overridable definition the strategy to use for supervising child actors.
User overridable definition the strategy to use for supervising child actors.
- Inherited from:
- Actor
- Source:
- Actor.scala
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
- Inherited from:
- Actor
- Source:
- Actor.scala
Concrete fields
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.
- Source:
- PersistentFSMBase.scala
This case object is received in case of a state timeout.
This case object is received in case of a state timeout.
- Source:
- PersistentFSMBase.scala
Inherited fields
Implicits
Implicits
Convenience wrapper for using a total function instead of a partial function literal. To be used with onTransition.
Convenience wrapper for using a total function instead of a partial function literal. To be used with onTransition.
- Source:
- PersistentFSMBase.scala
Inherited implicits
Scala API: Stores the context for this actor, including self, and sender.
It is implicit to support operations such as forward.
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.
- Inherited from:
- Actor
- Source:
- Actor.scala
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
- Inherited from:
- Actor
- Source:
- Actor.scala