pekko/akka-docs/rst/scala/code/docs/persistence/PersistenceDocSpec.scala

/**
 * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
 */

package docs.persistence

import akka.actor.{ Actor, ActorRef, ActorSystem, Props }
import akka.persistence._
import com.typesafe.config.ConfigFactory

import scala.concurrent.duration._
import scala.language.postfixOps

object PersistenceDocSpec {

  trait SomeOtherMessage

  val persistentActor: ActorRef = ???

  val config =
    """
      //#auto-update-interval
      akka.persistence.view.auto-update-interval = 5s
      //#auto-update-interval
      //#auto-update
      akka.persistence.view.auto-update = off
      //#auto-update
    """

  object Recovery {
    trait MyPersistentActor1 extends PersistentActor {
      //#recover-on-start-disabled
      override def preStart() = ()
      //#recover-on-start-disabled
      //#recover-on-restart-disabled
      override def preRestart(reason: Throwable, message: Option[Any]) = ()
      //#recover-on-restart-disabled
    }

    trait MyPersistentActor2 extends PersistentActor {
      //#recover-on-start-custom
      override def preStart() {
        self ! Recover(toSequenceNr = 457L)
      }
      //#recover-on-start-custom
    }

    //#recover-explicit
    persistentActor ! Recover()
    //#recover-explicit

    class MyPersistentActor4 extends PersistentActor {
      override def persistenceId = "my-stable-persistence-id"

      //#recovery-completed

      override def receiveRecover: Receive = {
        case RecoveryCompleted =>
        // perform init after recovery, before any other messages
        //...
        case evt               => //...
      }

      override def receiveCommand: Receive = {
        case msg => //...
      }
      //#recovery-completed
    }
  }

  object NoRecovery {
    trait MyPersistentActor1 extends PersistentActor {
      //#recover-fully-disabled
      override def preStart() = self ! Recover(toSequenceNr = 0L)
      //#recover-fully-disabled
    }
  }

  object PersistenceId {
    trait PersistentActorMethods {
      //#persistence-id
      def persistenceId: String
      //#persistence-id
      //#recovery-status
      def recoveryRunning: Boolean
      def recoveryFinished: Boolean
      //#recovery-status
    }
    class MyPersistentActor1 extends PersistentActor with PersistentActorMethods {
      //#persistence-id-override
      override def persistenceId = "my-stable-persistence-id"
      //#persistence-id-override

      override def receiveRecover: Receive = {
        case _ =>
      }
      override def receiveCommand: Receive = {
        case _ =>
      }
    }
  }

  object AtLeastOnce {
    //#at-least-once-example
    import akka.actor.{ Actor, ActorPath }
    import akka.persistence.AtLeastOnceDelivery

    case class Msg(deliveryId: Long, s: String)
    case class Confirm(deliveryId: Long)

    sealed trait Evt
    case class MsgSent(s: String) extends Evt
    case class MsgConfirmed(deliveryId: Long) extends Evt

    class MyPersistentActor(destination: ActorPath)
      extends PersistentActor with AtLeastOnceDelivery {

      override def persistenceId: String = "persistence-id"

      override def receiveCommand: Receive = {
        case s: String           => persist(MsgSent(s))(updateState)
        case Confirm(deliveryId) => persist(MsgConfirmed(deliveryId))(updateState)
      }

      override def receiveRecover: Receive = {
        case evt: Evt => updateState(evt)
      }

      def updateState(evt: Evt): Unit = evt match {
        case MsgSent(s) =>
          deliver(destination, deliveryId => Msg(deliveryId, s))

        case MsgConfirmed(deliveryId) => confirmDelivery(deliveryId)
      }
    }

    class MyDestination extends Actor {
      def receive = {
        case Msg(deliveryId, s) =>
          // ...
          sender() ! Confirm(deliveryId)
      }
    }
    //#at-least-once-example
  }

  object SaveSnapshot {

    class MyPersistentActor extends PersistentActor {
      override def persistenceId = "my-stable-persistence-id"

      //#save-snapshot
      var state: Any = _

      override def receiveCommand: Receive = {
        case "snap"                                => saveSnapshot(state)
        case SaveSnapshotSuccess(metadata)         => // ...
        case SaveSnapshotFailure(metadata, reason) => // ...
      }
      //#save-snapshot

      override def receiveRecover: Receive = ???
    }
  }

  object OfferSnapshot {
    class MyPersistentActor extends PersistentActor {
      override def persistenceId = "my-stable-persistence-id"

      //#snapshot-offer
      var state: Any = _

      override def receiveRecover: Receive = {
        case SnapshotOffer(metadata, offeredSnapshot) => state = offeredSnapshot
        case RecoveryCompleted                        =>
        case event                                    => // ...
      }
      //#snapshot-offer

      override def receiveCommand: Receive = ???
    }

    import akka.actor.Props

    //#snapshot-criteria
    persistentActor ! Recover(fromSnapshot = SnapshotSelectionCriteria(
      maxSequenceNr = 457L,
      maxTimestamp = System.currentTimeMillis))
    //#snapshot-criteria
  }

  object PersistAsync {

    //#persist-async
    class MyPersistentActor extends PersistentActor {

      override def persistenceId = "my-stable-persistence-id"

      override def receiveRecover: Receive = {
        case _ => // handle recovery here
      }

      override def receiveCommand: Receive = {
        case c: String => {
          sender() ! c
          persistAsync(s"evt-$c-1") { e => sender() ! e }
          persistAsync(s"evt-$c-2") { e => sender() ! e }
        }
      }
    }

    // usage
    persistentActor ! "a"
    persistentActor ! "b"

    // possible order of received messages:
    // a
    // b
    // evt-a-1
    // evt-a-2
    // evt-b-1
    // evt-b-2

    //#persist-async
  }

  object Defer {

    //#defer
    class MyPersistentActor extends PersistentActor {

      override def persistenceId = "my-stable-persistence-id"

      override def receiveRecover: Receive = {
        case _ => // handle recovery here
      }

      override def receiveCommand: Receive = {
        case c: String => {
          sender() ! c
          persistAsync(s"evt-$c-1") { e => sender() ! e }
          persistAsync(s"evt-$c-2") { e => sender() ! e }
          defer(s"evt-$c-3") { e => sender() ! e }
        }
      }
    }
    //#defer

    //#defer-caller
    persistentActor ! "a"
    persistentActor ! "b"

    // order of received messages:
    // a
    // b
    // evt-a-1
    // evt-a-2
    // evt-a-3
    // evt-b-1
    // evt-b-2
    // evt-b-3

    //#defer-caller
  }

  object View {
    import akka.actor.Props

    val system: ActorSystem = ???

    //#view
    class MyView extends PersistentView {
      override def persistenceId: String = "some-persistence-id"
      override def viewId: String = "some-persistence-id-view"

      def receive: Receive = {
        case payload if isPersistent =>
        // handle message from journal...
        case payload                 =>
        // handle message from user-land...
      }
    }
    //#view

    //#view-update
    val view = system.actorOf(Props[MyView])
    view ! Update(await = true)
    //#view-update
  }

}