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org.apache.pekko.persistence

PersistentActor

trait PersistentActor extends Eventsourced with PersistenceIdentity

Scala API: A persistent Actor - can be used to implement command or Event Sourcing.

Source
PersistentActor.scala
Type Hierarchy
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Inherited
  1. PersistentActor
  2. Eventsourced
  3. PersistenceRecovery
  4. PersistenceIdentity
  5. PersistenceStash
  6. StashFactory
  7. Stash
  8. RequiresMessageQueue
  9. UnrestrictedStash
  10. StashSupport
  11. Snapshotter
  12. Actor
  13. AnyRef
  14. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Type Members

  1. type Receive = PartialFunction[Any, Unit]
    Definition Classes
    Actor

Abstract Value Members

  1. abstract def persistenceId: String

    Id of the persistent entity for which messages should be replayed.

    Id of the persistent entity for which messages should be replayed.

    Definition Classes
    PersistenceIdentity
  2. abstract def receiveCommand: Receive

    Command handler.

    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.

    Definition Classes
    Eventsourced
  3. abstract def receiveRecover: Receive

    Recovery handler that receives persisted events during recovery.

    Recovery handler that receives persisted events during recovery. If a state snapshot has been captured and saved, this handler will receive a pekko.persistence.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.

    Definition Classes
    Eventsourced
    See also

    pekko.persistence.Recovery

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from PersistentActor toany2stringadd[PersistentActor] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (PersistentActor, B)
    Implicit
    This member is added by an implicit conversion from PersistentActor toArrowAssoc[PersistentActor] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. def aroundPostRestart(reason: Throwable): Unit

    INTERNAL API.

    INTERNAL API.

    Attributes
    protected[pekko]
    Definition Classes
    Eventsourced → Actor
  7. def aroundPostStop(): Unit

    INTERNAL API.

    INTERNAL API.

    Attributes
    protected[pekko]
    Definition Classes
    Eventsourced → Actor
  8. def aroundPreRestart(reason: Throwable, message: Option[Any]): Unit

    INTERNAL API.

    INTERNAL API.

    Attributes
    protected[pekko]
    Definition Classes
    Eventsourced → Actor
  9. def aroundPreStart(): Unit

    INTERNAL API.

    INTERNAL API.

    Attributes
    protected[pekko]
    Definition Classes
    Eventsourced → Actor
  10. def aroundReceive(receive: Receive, message: Any): Unit

    INTERNAL API.

    INTERNAL API.

    receive

    current behavior.

    Attributes
    protected[pekko]
    Definition Classes
    Eventsourced → Actor
  11. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  12. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @HotSpotIntrinsicCandidate() @native()
  13. implicit val context: ActorContext

    Scala API: Stores the context for this actor, including self, and sender.

    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!

    pekko.actor.ActorContext is the Scala API. getContext returns a pekko.actor.AbstractActor.ActorContext, which is the Java API of the actor context.

    Definition Classes
    Actor
  14. def defer[A](event: A)(handler: (A) => Unit): Unit

    Defer the handler execution until all pending handlers have been executed.

    Defer the handler execution until all pending handlers have been executed. It is guaranteed that no new commands will be received by a persistent actor between a call to defer and the execution of its handler. Allows to define logic within the actor, which will respect the invocation-order-guarantee in respect to persistAsync or persist calls. That is, if persistAsync or persist 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, use persist or persistAsync instead 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.

    event

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

    handler

    handler for the given event

  15. def deferAsync[A](event: A)(handler: (A) => Unit): Unit

    Defer the handler execution until all pending handlers have been executed.

    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 or persist calls. That is, if persistAsync or persist was invoked before deferAsync, the corresponding handlers will be invoked in the same order as they were registered in.

    This call will NOT result in event being persisted, use persist or persistAsync instead 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.

    event

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

    handler

    handler for the given event

  16. def deleteMessages(toSequenceNr: Long): Unit

    Permanently deletes all persistent messages with sequence numbers less than or equal toSequenceNr.

    Permanently deletes all persistent messages with sequence numbers less than or equal toSequenceNr.

    If the delete is successful a pekko.persistence.DeleteMessagesSuccess will be sent to the actor. If the delete fails a pekko.persistence.DeleteMessagesFailure will be sent to the actor.

    The given toSequenceNr must be less than or equal to Eventsourced#lastSequenceNr, otherwise pekko.persistence.DeleteMessagesFailure is sent to the actor without performing the delete. All persistent messages may be deleted without specifying the actual sequence number by using Long.MaxValue as the toSequenceNr.

    toSequenceNr

    upper sequence number (inclusive) bound of persistent messages to be deleted.

    Definition Classes
    Eventsourced
  17. def deleteSnapshot(sequenceNr: Long): Unit

    Deletes the snapshot identified by sequenceNr.

    Deletes the snapshot identified by sequenceNr.

    The PersistentActor will be notified about the status of the deletion via an DeleteSnapshotSuccess or DeleteSnapshotFailure message.

    Definition Classes
    Snapshotter
  18. def deleteSnapshots(criteria: SnapshotSelectionCriteria): Unit

    Deletes all snapshots matching criteria.

    Deletes all snapshots matching criteria.

    The PersistentActor will be notified about the status of the deletion via an DeleteSnapshotsSuccess or DeleteSnapshotsFailure message.

    Definition Classes
    Snapshotter
  19. def ensuring(cond: (PersistentActor) => Boolean, msg: => Any): PersistentActor
    Implicit
    This member is added by an implicit conversion from PersistentActor toEnsuring[PersistentActor] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  20. def ensuring(cond: (PersistentActor) => Boolean): PersistentActor
    Implicit
    This member is added by an implicit conversion from PersistentActor toEnsuring[PersistentActor] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  21. def ensuring(cond: Boolean, msg: => Any): PersistentActor
    Implicit
    This member is added by an implicit conversion from PersistentActor toEnsuring[PersistentActor] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  22. def ensuring(cond: Boolean): PersistentActor
    Implicit
    This member is added by an implicit conversion from PersistentActor toEnsuring[PersistentActor] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  23. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  24. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  25. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @HotSpotIntrinsicCandidate() @native()
  26. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @HotSpotIntrinsicCandidate() @native()
  27. def internalStashOverflowStrategy: StashOverflowStrategy

    The returned pekko.persistence.StashOverflowStrategy object determines how to handle the message failed to stash when the internal Stash capacity exceeded.

    The returned pekko.persistence.StashOverflowStrategy object determines how to handle the message failed to stash when the internal Stash capacity exceeded.

    Definition Classes
    PersistenceStash
  28. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  29. def journalPluginId: String

    Configuration id of the journal plugin servicing this persistent actor.

    Configuration id of the journal plugin servicing this persistent actor. When empty, looks in pekko.persistence.journal.plugin to find configuration entry path. When configured, uses journalPluginId as absolute path to the journal configuration entry. Configuration entry must contain few required fields, such as class. See src/main/resources/reference.conf.

    Definition Classes
    PersistenceIdentity
  30. def lastSequenceNr: Long

    Highest received sequence number so far or 0L if this actor hasn't replayed or stored any persistent events yet.

    Highest received sequence number so far or 0L if this actor hasn't replayed or stored any persistent events yet.

    Definition Classes
    Eventsourced
  31. def loadSnapshot(persistenceId: String, criteria: SnapshotSelectionCriteria, toSequenceNr: Long): Unit

    Instructs the snapshot store to load the specified snapshot and send it via an SnapshotOffer to the running PersistentActor.

    Instructs the snapshot store to load the specified snapshot and send it via an SnapshotOffer to the running PersistentActor.

    Definition Classes
    Snapshotter
  32. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  33. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @HotSpotIntrinsicCandidate() @native()
  34. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @HotSpotIntrinsicCandidate() @native()
  35. def onPersistFailure(cause: Throwable, event: Any, seqNr: Long): Unit

    Called when persist fails.

    Called when persist fails. By default it logs the error. Subclass may override to customize logging and for example send negative acknowledgment to sender.

    The actor is always stopped after this method has been invoked.

    Note that the event may or may not have been saved, depending on the type of failure.

    cause

    failure cause.

    event

    the event that was to be persisted

    Attributes
    protected
    Definition Classes
    Eventsourced
    Annotations
    @InternalStableApi()
  36. def onPersistRejected(cause: Throwable, event: Any, seqNr: Long): Unit

    Called when the journal rejected persist of an event.

    Called when the journal rejected persist of an event. The event was not stored. By default this method logs the problem as an error, and the actor continues. The callback handler that was passed to the persist method will not be invoked.

    cause

    failure cause

    event

    the event that was to be persisted

    Attributes
    protected
    Definition Classes
    Eventsourced
    Annotations
    @InternalStableApi()
  37. def onRecoveryFailure(cause: Throwable, event: Option[Any]): Unit

    Called whenever a message replay fails.

    Called whenever a message replay fails. By default it logs the error.

    Subclass may override to customize logging.

    The actor is always stopped after this method has been invoked.

    cause

    failure cause.

    event

    the event that was processed in receiveRecover, if the exception was thrown there

    Attributes
    protected
    Definition Classes
    Eventsourced
  38. def persist[A](event: A)(handler: (A) => Unit): Unit

    Asynchronously persists event.

    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 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.

    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, #onPersistFailure 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 event 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.

    event

    event to be persisted

    handler

    handler for each persisted event

  39. def persistAll[A](events: Seq[A])(handler: (A) => Unit): Unit

    Asynchronously persists events in specified order.

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

    events

    events to be persisted

    handler

    handler for each persisted events

  40. def persistAllAsync[A](events: Seq[A])(handler: (A) => Unit): Unit

    Asynchronously persists events in specified order.

    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.

    events

    events to be persisted

    handler

    handler for each persisted events

  41. def persistAsync[A](event: A)(handler: (A) => Unit): Unit

    Asynchronously persists event.

    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 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, #onPersistFailure 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 event 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.

    event

    event to be persisted

    handler

    handler for each persisted event

  42. def postRestart(reason: Throwable): Unit

    User overridable callback: By default it calls preStart().

    User overridable callback: By default it calls preStart().

    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.

    Definition Classes
    Actor
    Annotations
    @throws(classOf[Exception])
  43. def postStop(): Unit

    Overridden callback.

    Overridden callback. Prepends all messages in the stash to the mailbox and clears the stash. Must be called when overriding this method, otherwise stashed messages won't be propagated to DeadLetters when actor stops.

    Definition Classes
    UnrestrictedStashActor
    Annotations
    @throws(classOf[Exception])
  44. def preRestart(reason: Throwable, message: Option[Any]): Unit

    Overridden callback.

    Overridden callback. Prepends all messages in the stash to the mailbox, clears the stash, stops all children and invokes the postStop() callback.

    reason

    the Throwable that caused the restart to happen

    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.

    Definition Classes
    UnrestrictedStashActor
    Annotations
    @throws(classOf[Exception])
  45. def preStart(): Unit

    User overridable callback.

    User overridable callback.

    Is called when an Actor is started. Actors are automatically started asynchronously when created. Empty default implementation.

    Definition Classes
    Actor
    Annotations
    @throws(classOf[Exception])
  46. def receive: Receive

    Scala API: This defines the initial actor behavior, it must return a partial function with the actor logic.

    Scala API: This defines the initial actor behavior, it must return a partial function with the actor logic.

    Definition Classes
    PersistentActorActor
  47. def recovery: Recovery

    Called when the persistent actor is started for the first time.

    Called when the persistent actor is started for the first time. The returned pekko.persistence.Recovery object defines how the Actor will recover its persistent state before handling the first incoming message.

    To skip recovery completely return Recovery.none.

    Definition Classes
    PersistenceRecovery
  48. def recoveryFinished: Boolean

    Returns true if this persistent actor has successfully finished recovery.

    Returns true if this persistent actor has successfully finished recovery.

    Definition Classes
    Eventsourced
  49. def recoveryRunning: Boolean

    Returns true if this persistent actor is currently recovering.

    Returns true if this persistent actor is currently recovering.

    Definition Classes
    Eventsourced
  50. def saveSnapshot(snapshot: Any): Unit

    Saves a snapshot of this snapshotter's state.

    Saves a snapshot of this snapshotter's state.

    The PersistentActor will be notified about the success or failure of this via an SaveSnapshotSuccess or SaveSnapshotFailure message.

    Definition Classes
    Snapshotter
  51. implicit final val self: ActorRef

    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
    

    Definition Classes
    Actor
  52. final def sender(): ActorRef

    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 pekko.actor.ActorSystem.

    WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!

    Definition Classes
    Actor
  53. def snapshotPluginId: String

    Configuration id of the snapshot plugin servicing this persistent actor.

    Configuration id of the snapshot plugin servicing this persistent actor. When empty, looks in pekko.persistence.snapshot-store.plugin to find configuration entry path. When configured, uses snapshotPluginId as absolute path to the snapshot store configuration entry. Configuration entry must contain few required fields, such as class. See src/main/resources/reference.conf.

    Definition Classes
    PersistenceIdentity
  54. def snapshotSequenceNr: Long

    Returns lastSequenceNr.

    Returns lastSequenceNr.

    Definition Classes
    Eventsourced → Snapshotter
  55. def snapshotterId: String

    Returns persistenceId.

    Returns persistenceId.

    Definition Classes
    Eventsourced → Snapshotter
  56. def stash(): Unit

    Adds the current message (the message that the actor received last) to the actor's stash.

    Adds the current message (the message that the actor received last) to the actor's stash.

    Definition Classes
    Eventsourced → StashSupport
    Exceptions thrown

    java.lang.IllegalStateException if the same message is stashed more than once

    pekko.actor.StashOverflowException in case of a stash capacity violation

  57. def supervisorStrategy: SupervisorStrategy

    User overridable definition the strategy to use for supervising child actors.

    User overridable definition the strategy to use for supervising child actors.

    Definition Classes
    Actor
  58. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  59. def toString(): String
    Definition Classes
    AnyRef → Any
  60. def unhandled(message: Any): Unit

    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 pekko.actor.DeathPactException (in case of an unhandled pekko.actor.Terminated message) or publishes an pekko.actor.UnhandledMessage to the actor's system's pekko.event.EventStream

    Definition Classes
    Eventsourced → Actor
  61. def unstashAll(): Unit

    Prepends all messages in the stash to the mailbox, and then clears the stash.

    Prepends all messages in the stash to the mailbox, and then clears the stash.

    Messages from the stash are enqueued to the mailbox until the capacity of the mailbox (if any) has been reached. In case a bounded mailbox overflows, a MessageQueueAppendFailedException is thrown.

    The stash is guaranteed to be empty after calling unstashAll().

    Definition Classes
    Eventsourced → StashSupport
  62. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  63. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  64. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])

Deprecated Value Members

  1. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable]) @Deprecated
    Deprecated

    (Since version 9)

  2. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from PersistentActor toStringFormat[PersistentActor] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @deprecated @inline()
    Deprecated

    (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), or use the f"" string interpolator. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters.

  3. def [B](y: B): (PersistentActor, B)
    Implicit
    This member is added by an implicit conversion from PersistentActor toArrowAssoc[PersistentActor] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) Use -> instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

Inherited from Eventsourced

Inherited from PersistenceRecovery

Inherited from PersistenceIdentity

Inherited from PersistenceStash

Inherited from StashFactory

Inherited from Stash

Inherited from UnrestrictedStash

Inherited from StashSupport

Inherited from Snapshotter

Inherited from Actor

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd fromPersistentActor to any2stringadd[PersistentActor]

Inherited by implicit conversion StringFormat fromPersistentActor to StringFormat[PersistentActor]

Inherited by implicit conversion Ensuring fromPersistentActor to Ensuring[PersistentActor]

Inherited by implicit conversion ArrowAssoc fromPersistentActor to ArrowAssoc[PersistentActor]

Ungrouped