Java API constructor with default values.
Full Java API constructor.
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
Manages a cluster wide singleton actor instance, i.e. at most one singleton instance is running at any point in time. The ClusterSingletonManager is supposed to be started on all nodes in the cluster with
actorOf. The actual singleton is started on the leader node of the cluster by creating a child actor from the suppliedsingletonProps.The singleton actor is always running on the leader member, which is nothing more than the address currently sorted first in the member ring. This can change when adding or removing members. A graceful hand over can normally be performed when joining a new node that becomes leader or removing current leader node. Be aware that there is a short time period when there is no active singleton during the hand-over process.
The singleton actor can at any time send a message to its parent ClusterSingletonManager and this message will be passed to the
singletonPropsfactory on the new leader node when a graceful hand-over is performed.The cluster failure detector will notice when a leader node becomes unreachable due to things like JVM crash, hard shut down, or network failure. Then a new leader node will take over and a new singleton actor is created. For these failure scenarios there will not be a graceful hand-over, but more than one active singletons is prevented by all reasonable means. Some corner cases are eventually resolved by configurable timeouts.
You access the singleton actor with
actorForusing the names you have specified when creating the ClusterSingletonManager. You can subscribe to akka.cluster.ClusterEvent.LeaderChanged to keep track of which node it is supposed to be running on. Alternatively the singleton actor may broadcast its existence when it is started.Arguments
singletonProps Factory for akka.actor.Props of the singleton actor instance. The
Optionparameter is the thehandOverDatasent from previous singleton.handOverDatamight be None when no hand-over took place, or when the there is no need for sending data to the new singleton. ThehandOverDatais typically passed as parameter to the constructor of the singleton actor.singletonName The actor name of the child singleton actor.
terminationMessage When handing over to a new leader node this
terminationMessageis sent to the singleton actor to tell it to finish its work, close resources, and stop. It can sending a message back to the parent ClusterSingletonManager, which will passed to thesingletonPropsfactory on the new leader node. The hand-over to the new leader node is completed when the singleton actor is terminated. Note that akka.actor.PoisonPill is a perfectly fineterminationMessageif you only need to stop the actor.maxHandOverRetries When a node is becoming leader it sends hand-over request to previous leader. This is retried with the
retryIntervaluntil the previous leader confirms that the hand over has started, or thismaxHandOverRetrieslimit has been reached. If the retry limit is reached it takes the decision to be the new leader if previous leader is unknown (typically removed or downed), otherwise it initiates a new round by throwing akka.contrib.pattern.ClusterSingletonManagerIsStuck and expecting restart with fresh state. For a cluster with many members you might need to increase this retry limit because it takes longer time to propagate changes across all nodes.maxTakeOverRetries When a leader node is not leader any more it sends take over request to the new leader to initiate the normal hand-over process. This is especially useful when new node joins and becomes leader immediately, without knowing who was previous leader. This is retried with the
retryIntervaluntil this retry limit has been reached. If the retry limit is reached it initiates a new round by throwing akka.contrib.pattern.ClusterSingletonManagerIsStuck and expecting restart with fresh state. This will also cause the singleton actor to be stopped.maxTakeOverRetriesmust be less thanmaxHandOverRetriesto ensure that new leader doesn't start singleton actor before previous is stopped for certain corner cases.loggingEnabled Logging of what is going on at info log level.