ea9617aa25
* Update Persistence Snapshot documentation (#22233) * Use copy of ExampleState as it is mutable
60 lines
1.5 KiB
Scala
60 lines
1.5 KiB
Scala
package scala.docs.persistence
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//#persistent-actor-example
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import akka.actor._
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import akka.persistence._
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case class Cmd(data: String)
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case class Evt(data: String)
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case class ExampleState(events: List[String] = Nil) {
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def updated(evt: Evt): ExampleState = copy(evt.data :: events)
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def size: Int = events.length
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override def toString: String = events.reverse.toString
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}
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class ExamplePersistentActor extends PersistentActor {
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override def persistenceId = "sample-id-1"
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var state = ExampleState()
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def updateState(event: Evt): Unit =
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state = state.updated(event)
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def numEvents =
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state.size
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val receiveRecover: Receive = {
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case evt: Evt => updateState(evt)
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case SnapshotOffer(_, snapshot: ExampleState) => state = snapshot
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}
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val snapShotInterval = 1000
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val receiveCommand: Receive = {
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case Cmd(data) =>
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persist(Evt(s"${data}-${numEvents}")) { event =>
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updateState(event)
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context.system.eventStream.publish(event)
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if (lastSequenceNr % snapShotInterval == 0 && lastSequenceNr != 0)
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saveSnapshot(state)
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}
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case "print" => println(state)
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}
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}
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//#persistent-actor-example
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object PersistentActorExample extends App {
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val system = ActorSystem("example")
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val persistentActor = system.actorOf(Props[ExamplePersistentActor], "persistentActor-4-scala")
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persistentActor ! Cmd("foo")
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persistentActor ! Cmd("baz")
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persistentActor ! Cmd("bar")
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persistentActor ! Cmd("buzz")
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persistentActor ! "print"
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Thread.sleep(10000)
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system.terminate()
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}
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