trait PersistentActor extends Eventsourced with PersistenceIdentity
Scala API: A persistent Actor - can be used to implement command or Event Sourcing.
- Source
- PersistentActor.scala
- Alphabetic
- By Inheritance
- PersistentActor
- Eventsourced
- PersistenceRecovery
- PersistenceIdentity
- PersistenceStash
- StashFactory
- Stash
- RequiresMessageQueue
- UnrestrictedStash
- StashSupport
- Snapshotter
- Actor
- AnyRef
- Any
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
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- Public
- Protected
Type Members
- type Receive = PartialFunction[Any, Unit]
- Definition Classes
- Actor
Abstract Value Members
- 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
- 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
- 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
Concrete Value Members
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- final def ##: Int
- Definition Classes
- AnyRef → Any
- 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
- 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()
- final def ==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- def aroundPostRestart(reason: Throwable): Unit
INTERNAL API.
- def aroundPostStop(): Unit
INTERNAL API.
- def aroundPreRestart(reason: Throwable, message: Option[Any]): Unit
INTERNAL API.
- def aroundPreStart(): Unit
INTERNAL API.
- def aroundReceive(receive: Receive, message: Any): Unit
INTERNAL API.
- final def asInstanceOf[T0]: T0
- Definition Classes
- Any
- def clone(): AnyRef
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.CloneNotSupportedException]) @HotSpotIntrinsicCandidate() @native()
- 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
- 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 itshandler
. Allows to define logic within the actor, which will respect the invocation-order-guarantee in respect topersistAsync
orpersist
calls. That is, ifpersistAsync
orpersist
was invoked beforedefer
, the corresponding handlers will be invoked in the same order as they were registered in.This call will NOT result in
event
being persisted, usepersist
orpersistAsync
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
- 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
orpersist
calls. That is, ifpersistAsync
orpersist
was invoked beforedeferAsync
, the corresponding handlers will be invoked in the same order as they were registered in.This call will NOT result in
event
being persisted, usepersist
orpersistAsync
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
- 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 usingLong.MaxValue
as thetoSequenceNr
.- toSequenceNr
upper sequence number (inclusive) bound of persistent messages to be deleted.
- Definition Classes
- Eventsourced
- 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
- 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
- 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
- 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
- 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
- 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
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def equals(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef → Any
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- def hashCode(): Int
- Definition Classes
- AnyRef → Any
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- 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
- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- 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, usesjournalPluginId
as absolute path to the journal configuration entry. Configuration entry must contain few required fields, such asclass
. Seesrc/main/resources/reference.conf
.- Definition Classes
- PersistenceIdentity
- 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
- 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
- final def ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- final def notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- final def notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- 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()
- 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 thepersist
method will not be invoked.- cause
failure cause
- event
the event that was to be persisted
- Attributes
- protected
- Definition Classes
- Eventsourced
- Annotations
- @InternalStableApi()
- 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
- 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 topersist
and the execution of itshandler
. This also holds for multiplepersist
calls per received command. Internally, this is achieved by stashing new commands and unstashing them when theevent
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. Thesender
of a persisted event is the sender of the corresponding command. This means that one can reply to a command sender within an eventhandler
.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
- 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 callingpersist[A](event: A)(handler: A => Unit)
multiple times with the samehandler
, except thatevents
are persisted atomically with this method.- events
events to be persisted
- handler
handler for each persisted
events
- 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 callingpersistAsync[A](event: A)(handler: A => Unit)
multiple times with the samehandler
, except thatevents
are persisted atomically with this method.- events
events to be persisted
- handler
handler for each persisted
events
- 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 topersist
and executing it'shandler
. 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 plainpersist
method.An event
handler
may close over persistent actor state and modify it. Thesender
of a persisted event is the sender of the corresponding command. This means that one can reply to a command sender within an eventhandler
.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
- 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])
- 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
- UnrestrictedStash → Actor
- Annotations
- @throws(classOf[Exception])
- 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
- UnrestrictedStash → Actor
- Annotations
- @throws(classOf[Exception])
- 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])
- 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
- PersistentActor → Actor
- 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
- 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
- def recoveryRunning: Boolean
Returns
true
if this persistent actor is currently recovering.Returns
true
if this persistent actor is currently recovering.- Definition Classes
- Eventsourced
- 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
- 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
- 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
- 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, usessnapshotPluginId
as absolute path to the snapshot store configuration entry. Configuration entry must contain few required fields, such asclass
. Seesrc/main/resources/reference.conf
.- Definition Classes
- PersistenceIdentity
- def snapshotSequenceNr: Long
Returns
lastSequenceNr
.Returns
lastSequenceNr
.- Definition Classes
- Eventsourced → Snapshotter
- def snapshotterId: String
Returns
persistenceId
.Returns
persistenceId
.- Definition Classes
- Eventsourced → Snapshotter
- 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 oncepekko.actor.StashOverflowException
in case of a stash capacity violation
- 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
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
- def toString(): String
- Definition Classes
- AnyRef → Any
- 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
- 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
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException]) @native()
- final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
Deprecated Value Members
- def finalize(): Unit
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable]) @Deprecated
- Deprecated
(Since version 9)
- 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 ofvalue.formatted(formatString)
, or use thef""
string interpolator. In Java 15 and later,formatted
resolves to the new method in String which has reversed parameters.
- 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.