akka.persistence

Class UntypedPersistentActor

java.lang.Object

akka.actor.UntypedActor

akka.persistence.UntypedPersistentActor

All Implemented Interfaces:

Actor, Stash, StashFactory, StashSupport, UnrestrictedStash, RequiresMessageQueue<DequeBasedMessageQueueSemantics>, Eventsourced, PersistenceIdentity, PersistenceRecovery, PersistenceStash, Snapshotter

Direct Known Subclasses:

UntypedPersistentActorWithAtLeastOnceDelivery

public abstract class UntypedPersistentActor
extends UntypedActor
implements Eventsourced, PersistenceIdentity

Java API: an persistent actor - can be used to implement command or event sourcing.

Nested Class Summary

Nested classes/interfaces inherited from interface akka.persistence.Eventsourced

Eventsourced.AsyncHandlerInvocation, Eventsourced.AsyncHandlerInvocation$, Eventsourced.PendingHandlerInvocation, Eventsourced.RecoveryTick, Eventsourced.RecoveryTick$, Eventsourced.StashingHandlerInvocation, Eventsourced.StashingHandlerInvocation$, Eventsourced.State

Nested classes/interfaces inherited from interface akka.actor.Actor

Actor.emptyBehavior$, Actor.ignoringBehavior$

Constructor Summary

Constructors

Constructor and Description
UntypedPersistentActor()

Method Summary

Modifier and Type	Method and Description
<A> void	deferAsync(A event, Procedure<A> handler) Defer the handler execution until all pending handlers have been executed.
protected ActorRef	journal()
DequeBasedMessageQueueSemantics	mailbox()
void	onReceive(java.lang.Object message) To be implemented by concrete UntypedActor, this defines the behavior of the UntypedActor.
abstract void	onReceiveCommand(java.lang.Object msg) Java API: command handler.
abstract void	onReceiveRecover(java.lang.Object msg) Java API: recovery handler that receives persisted events during recovery.
<A> void	persist(A event, Procedure<A> handler) Java API: asynchronously persists event.
<A> void	persist(java.lang.Iterable<A> events, Procedure<A> handler) Deprecated. use persistAll instead. Since 2.4.
<A> void	persistAll(java.lang.Iterable<A> events, Procedure<A> handler) Java API: asynchronously persists events in specified order.
<A> void	persistAllAsync(java.lang.Iterable<A> events, Procedure<A> handler) JAVA API: asynchronously persists events in specified order.
<A> void	persistAsync(A event, Procedure<A> handler) JAVA API: asynchronously persists event.
scala.PartialFunction<java.lang.Object,scala.runtime.BoxedUnit>	receiveCommand() Command handler.
scala.PartialFunction<java.lang.Object,scala.runtime.BoxedUnit>	receiveRecover() Recovery handler that receives persisted events during recovery.
protected ActorRef	snapshotStore() Snapshot store plugin actor.

Methods inherited from class akka.actor.UntypedActor

context, getContext, getSelf, getSender, postRestart, postStop, preRestart, preStart, receive, self, supervisorStrategy, unhandled

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface akka.persistence.Eventsourced

aroundPostRestart, aroundPostStop, aroundPreRestart, aroundPreStart, aroundReceive, changeState, deferAsync, deleteMessages, flushBatch, flushJournalBatch, lastSequenceNr, log, nextSequenceNr, onPersistFailure, onPersistRejected, onRecoveryFailure, onReplaySuccess, peekApplyHandler, persist, persist, persistAll, persistAllAsync, persistAsync, persistAsync, recovering, recoveryFinished, recoveryRunning, recoveryStarted, requestRecoveryPermit, setLastSequenceNr, snapshotSequenceNr, snapshotterId, startRecovery, stashInternally, unhandled, unstashAll, unstashInternally, updateLastSequenceNr, waitingRecoveryPermit

Methods inherited from interface akka.persistence.Snapshotter

deleteSnapshot, deleteSnapshots, loadSnapshot, saveSnapshot

Methods inherited from interface akka.persistence.PersistenceStash

internalStashOverflowStrategy

Methods inherited from interface akka.actor.Actor

context, postRestart, preStart, receive, self, sender, supervisorStrategy

Methods inherited from interface akka.actor.StashSupport

actorCell, clearStash, context, enqueueFirst, prepend, self, stash, unstash, unstashAll

Methods inherited from interface akka.actor.StashFactory

createStash

Methods inherited from interface akka.persistence.PersistenceIdentity

journalPluginId, persistenceId, snapshotPluginId

Methods inherited from interface akka.persistence.PersistenceRecovery

recovery

Constructor Detail

UntypedPersistentActor

public UntypedPersistentActor()

Method Detail

journal

protected ActorRef journal()

Specified by:

journal in interface Eventsourced

snapshotStore

protected ActorRef snapshotStore()

Description copied from interface: Snapshotter

Snapshot store plugin actor.

Specified by:

snapshotStore in interface Eventsourced

Specified by:

snapshotStore in interface Snapshotter

mailbox

public DequeBasedMessageQueueSemantics mailbox()

Specified by:

mailbox in interface StashSupport

onReceive

public final void onReceive(java.lang.Object message)

Description copied from class: UntypedActor

To be implemented by concrete UntypedActor, this defines the behavior of the UntypedActor.

Specified by:

onReceive in class UntypedActor

Parameters:

message - (undocumented)

receiveRecover

public final scala.PartialFunction<java.lang.Object,scala.runtime.BoxedUnit> receiveRecover()

Description copied from interface: Eventsourced

Recovery handler that receives persisted events during recovery. If a state snapshot has been captured and saved, this handler will receive a SnapshotOffer message followed by events that are younger than the offered snapshot.

This handler must not have side-effects other than changing persistent actor state i.e. it should not perform actions that may fail, such as interacting with external services, for example.

If there is a problem with recovering the state of the actor from the journal, the error will be logged and the actor will be stopped.

Specified by:

receiveRecover in interface Eventsourced

Returns:

(undocumented)

See Also:

Recovery

receiveCommand

public final scala.PartialFunction<java.lang.Object,scala.runtime.BoxedUnit> receiveCommand()

Description copied from interface: Eventsourced

Command handler. Typically validates commands against current state (and/or by communication with other actors). On successful validation, one or more events are derived from a command and these events are then persisted by calling persist.

Specified by:

receiveCommand in interface Eventsourced

Returns:

(undocumented)

persist

public <A> void persist(A event,
                        Procedure<A> handler)

Java API: asynchronously persists event. On successful persistence, handler is called with the persisted event. It is guaranteed that no new commands will be received by a persistent actor between a call to persist and the execution of its handler. This also holds for multiple persist calls per received command. Internally, this is achieved by stashing new commands and unstashing them when the event has been persisted and handled. The stash used for that is an internal stash which doesn't interfere with the inherited user stash.

An event handler may close over persistent actor state and modify it. The getSender() of a persisted event is the sender of the corresponding command. This means that one can reply to a command sender within an event handler.

Within an event handler, applications usually update persistent actor state using persisted event data, notify listeners and reply to command senders.

If persistence of an event fails, Eventsourced.onPersistFailure(java.lang.Throwable, java.lang.Object, long) will be invoked and the actor will unconditionally be stopped. The reason that it cannot resume when persist fails is that it is unknown if the even was actually persisted or not, and therefore it is in an inconsistent state. Restarting on persistent failures will most likely fail anyway, since the journal is probably unavailable. It is better to stop the actor and after a back-off timeout start it again.

Parameters:

event - event to be persisted.

handler - handler for each persisted event

persistAll

public <A> void persistAll(java.lang.Iterable<A> events,
                           Procedure<A> handler)

Java API: asynchronously persists events in specified order. This is equivalent to calling persist[A](event: A, handler: Procedure[A]) multiple times with the same handler, except that events are persisted atomically with this method.

Parameters:

events - events to be persisted.

handler - handler for each persisted events

persist

public <A> void persist(java.lang.Iterable<A> events,
                        Procedure<A> handler)

Deprecated. use persistAll instead. Since 2.4.

persistAsync

public <A> void persistAsync(A event,
                             Procedure<A> handler)

JAVA API: asynchronously persists event. On successful persistence, handler is called with the persisted event.

Unlike persist the persistent actor will continue to receive incoming commands between the call to persist and executing it's handler. This asynchronous, non-stashing, version of of persist should be used when you favor throughput over the "command-2 only processed after command-1 effects' have been applied" guarantee, which is provided by the plain persist(A, akka.japi.Procedure<A>) method.

An event handler may close over persistent actor state and modify it. The sender of a persisted event is the sender of the corresponding command. This means that one can reply to a command sender within an event handler.

If persistence of an event fails, Eventsourced.onPersistFailure(java.lang.Throwable, java.lang.Object, long) will be invoked and the actor will unconditionally be stopped. The reason that it cannot resume when persist fails is that it is unknown if the even was actually persisted or not, and therefore it is in an inconsistent state. Restarting on persistent failures will most likely fail anyway, since the journal is probably unavailable. It is better to stop the actor and after a back-off timeout start it again.

Parameters:

event - event to be persisted

handler - handler for each persisted event

persistAllAsync

public <A> void persistAllAsync(java.lang.Iterable<A> events,
                                Procedure<A> handler)

JAVA API: asynchronously persists events in specified order. This is equivalent to calling persistAsync[A](event: A)(handler: A => Unit) multiple times with the same handler, except that events are persisted atomically with this method.

Parameters:

events - events to be persisted

handler - handler for each persisted events

deferAsync

public <A> void deferAsync(A event,
                           Procedure<A> handler)

Defer the handler execution until all pending handlers have been executed. Allows to define logic within the actor, which will respect the invocation-order-guarantee in respect to persistAsync calls. That is, if persistAsync was invoked before defer, the corresponding handlers will be invoked in the same order as they were registered in.

This call will NOT result in event being persisted, please use persist or persistAsync, if the given event should possible to replay.

If there are no pending persist handler calls, the handler will be called immediately.

If persistence of an earlier event fails, the persistent actor will stop, and the handler will not be run.

Parameters:

event - event to be handled in the future, when preceding persist operations have been processes

handler - handler for the given event

onReceiveRecover

public abstract void onReceiveRecover(java.lang.Object msg)
                               throws java.lang.Throwable

Java API: recovery handler that receives persisted events during recovery. If a state snapshot has been captured and saved, this handler will receive a SnapshotOffer message followed by events that are younger than the offered snapshot.

This handler must not have side-effects other than changing persistent actor state i.e. it should not perform actions that may fail, such as interacting with external services, for example.

If there is a problem with recovering the state of the actor from the journal, the error will be logged and the actor will be stopped.

Parameters:

msg - (undocumented)

Throws:

java.lang.Throwable

See Also:

Recovery

onReceiveCommand

public abstract void onReceiveCommand(java.lang.Object msg)
                               throws java.lang.Throwable

Java API: command handler. Typically validates commands against current state (and/or by communication with other actors). On successful validation, one or more events are derived from a command and these events are then persisted by calling persist.

Parameters:

msg - (undocumented)

Throws:

java.lang.Throwable