PersistentActor
Scala API: A persistent Actor - can be used to implement command or Event Sourcing.
- Source:
- PersistentActor.scala
Type members
Inherited types
Value members
Concrete methods
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.
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.
- Value parameters:
- event
event to be handled in the future, when preceding persist operations have been processes
- handler
handler for the given
event
- Source:
- PersistentActor.scala
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.
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.
- Value parameters:
- event
event to be handled in the future, when preceding persist operations have been processes
- handler
handler for the given
event
- Source:
- PersistentActor.scala
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.
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.
- Value parameters:
- event
event to be persisted
- handler
handler for each persisted
event
- Source:
- PersistentActor.scala
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.
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.
- Value parameters:
- events
events to be persisted
- handler
handler for each persisted
events
- Source:
- PersistentActor.scala
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.
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.
- Value parameters:
- events
events to be persisted
- handler
handler for each persisted
events
- Source:
- PersistentActor.scala
Asynchronously persists event
. On successful persistence, handler
is called with the
persisted 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.
- Value parameters:
- event
event to be persisted
- handler
handler for each persisted
event
- Source:
- PersistentActor.scala
Inherited methods
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 DeleteMessagesSuccess will be sent to the actor. If the delete fails a DeleteMessagesFailure will be sent to the actor.
The given toSequenceNr
must be less than or equal to Eventsourced#lastSequenceNr, otherwise
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
.
- Value parameters:
- toSequenceNr
upper sequence number (inclusive) bound of persistent messages to be deleted.
- Inherited from:
- Eventsourced
- Source:
- Eventsourced.scala
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.
- Inherited from:
- Snapshotter
- Source:
- Snapshotter.scala
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.
- Inherited from:
- Snapshotter
- Source:
- Snapshotter.scala
The returned StashOverflowStrategy object determines how to handle the message failed to stash when the internal Stash capacity exceeded.
The returned StashOverflowStrategy object determines how to handle the message failed to stash when the internal Stash capacity exceeded.
- Inherited from:
- PersistenceStash
- Source:
- Persistence.scala
Configuration id of the journal plugin servicing this persistent actor.
When empty, looks in akka.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
.
Configuration id of the journal plugin servicing this persistent actor.
When empty, looks in akka.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
.
- Inherited from:
- PersistenceIdentity
- Source:
- Persistence.scala
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.
- Inherited from:
- Eventsourced
- Source:
- Eventsourced.scala
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.
- Inherited from:
- Snapshotter
- Source:
- Snapshotter.scala
Id of the persistent entity for which messages should be replayed.
Id of the persistent entity for which messages should be replayed.
- Inherited from:
- PersistenceIdentity
- Source:
- Persistence.scala
User overridable callback: By default it calls preStart()
.
User overridable callback: By default it calls preStart()
.
- Value parameters:
- 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.
- Inherited from:
- Actor
- Source:
- Actor.scala
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.
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
- Inherited from:
- UnrestrictedStash
- Source:
- Stash.scala
Overridden callback. Prepends all messages in the stash to the mailbox, clears the stash, stops all children and invokes the postStop() callback.
Overridden callback. Prepends all messages in the stash to the mailbox, clears the stash, stops all children and invokes the postStop() callback.
- Definition Classes
- Inherited from:
- UnrestrictedStash
- Source:
- Stash.scala
User overridable callback.
User overridable callback.
Is called when an Actor is started. Actors are automatically started asynchronously when created. Empty default implementation.
- Inherited from:
- Actor
- Source:
- Actor.scala
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
.
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
.
- Inherited from:
- Eventsourced
- Source:
- Eventsourced.scala
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.
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.
- See also:
- Inherited from:
- Eventsourced
- Source:
- Eventsourced.scala
Called when the persistent actor is started for the first time. The returned Recovery object defines how the Actor will recover its persistent state before handling the first incoming message.
Called when the persistent actor is started for the first time. The returned Recovery object defines how the Actor will recover its persistent state before handling the first incoming message.
To skip recovery completely return Recovery.none
.
- Inherited from:
- PersistenceRecovery
- Source:
- Persistence.scala
Returns true
if this persistent actor has successfully finished recovery.
Returns true
if this persistent actor has successfully finished recovery.
- Inherited from:
- Eventsourced
- Source:
- Eventsourced.scala
Returns true
if this persistent actor is currently recovering.
Returns true
if this persistent actor is currently recovering.
- Inherited from:
- Eventsourced
- Source:
- Eventsourced.scala
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.
- Inherited from:
- Snapshotter
- Source:
- Snapshotter.scala
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.
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!
- Inherited from:
- Actor
- Source:
- Actor.scala
Configuration id of the snapshot plugin servicing this persistent actor.
When empty, looks in akka.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
.
Configuration id of the snapshot plugin servicing this persistent actor.
When empty, looks in akka.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
.
- Inherited from:
- PersistenceIdentity
- Source:
- Persistence.scala
Returns lastSequenceNr
.
Returns lastSequenceNr
.
- Inherited from:
- Eventsourced
- Source:
- Eventsourced.scala
Returns persistenceId
.
Returns persistenceId
.
- Definition Classes
- Eventsourced -> Snapshotter
- Inherited from:
- Eventsourced
- Source:
- Eventsourced.scala
User overridable definition the strategy to use for supervising child actors.
User overridable definition the strategy to use for supervising child actors.
- Inherited from:
- Actor
- Source:
- Actor.scala
Implicits
Inherited implicits
Scala API: Stores the context for this actor, including self, and sender.
It is implicit to support operations such as forward
.
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!
akka.actor.ActorContext is the Scala API. getContext
returns a
akka.actor.AbstractActor.ActorContext, which is the Java API of the actor
context.
- Inherited from:
- Actor
- Source:
- Actor.scala
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
- Inherited from:
- Actor
- Source:
- Actor.scala