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.

Cancel named timer, ensuring that the message is not subsequently delivered (no race).

Retrieve current rolling log in oldest-first order. The log is filled with each incoming event before processing by the user supplied state handler. The log entries are lost when this actor is restarted.

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.

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.

By default PersistentFSM.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. Calling this method again will overwrite the previous contents.

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.

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.

Set state timeout explicitly. This method can safely be used from within a state handler.

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.

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.

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.

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 pekko.actor.Actor#preStart and pekko.actor.Actor#postRestart.

Return current state data (i.e. object of type D)

Return current state name (i.e. object of type S)

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.

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".

Convenience wrapper for using a total function instead of a partial function literal. To be used with onTransition.

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.

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.

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.