Akka/Scala example source code file (SnapshotStore.scala)

This example Akka source code file (SnapshotStore.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Akka and Scala source code examples by using tags.

All credit for the original source code belongs to akka.io; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Akka tags/keywords

actor, akka, concurrent, deletesnapshots, future, loadsnapshot, loadsnapshotresult, pattern, persistence, savesnapshot, savesnapshotfailure, savesnapshotsuccess, snapshot, snapshotmetadata, snapshotselectioncriteria, string

The SnapshotStore.scala Akka example source code

/**
 * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
 * Copyright (C) 2012-2013 Eligotech BV.
 */

package akka.persistence.snapshot

import scala.concurrent.Future

import akka.actor._
import akka.pattern.pipe
import akka.persistence._

/**
 * Abstract snapshot store.
 */
trait SnapshotStore extends Actor {
  import SnapshotProtocol._
  import context.dispatcher

  private val extension = Persistence(context.system)
  private val publish = extension.settings.internal.publishPluginCommands

  final def receive = {
    case LoadSnapshot(persistenceId, criteria, toSequenceNr) ⇒
      val p = sender()
      loadAsync(persistenceId, criteria.limit(toSequenceNr)) map {
        sso ⇒ LoadSnapshotResult(sso, toSequenceNr)
      } recover {
        case e ⇒ LoadSnapshotResult(None, toSequenceNr)
      } pipeTo p
    case SaveSnapshot(metadata, snapshot) ⇒
      val p = sender()
      val md = metadata.copy(timestamp = System.currentTimeMillis)
      saveAsync(md, snapshot) map {
        _ ⇒ SaveSnapshotSuccess(md)
      } recover {
        case e ⇒ SaveSnapshotFailure(metadata, e)
      } to (self, p)
    case evt @ SaveSnapshotSuccess(metadata) ⇒
      saved(metadata)
      sender() ! evt // sender is persistentActor
    case evt @ SaveSnapshotFailure(metadata, _) ⇒
      delete(metadata)
      sender() ! evt // sender is persistentActor
    case d @ DeleteSnapshot(metadata) ⇒
      delete(metadata)
      if (publish) context.system.eventStream.publish(d)
    case d @ DeleteSnapshots(persistenceId, criteria) ⇒
      delete(persistenceId, criteria)
      if (publish) context.system.eventStream.publish(d)
  }

  //#snapshot-store-plugin-api
  /**
   * Plugin API: asynchronously loads a snapshot.
   *
   * @param persistenceId processor id.
   * @param criteria selection criteria for loading.
   */
  def loadAsync(persistenceId: String, criteria: SnapshotSelectionCriteria): Future[Option[SelectedSnapshot]]

  /**
   * Plugin API: asynchronously saves a snapshot.
   *
   * @param metadata snapshot metadata.
   * @param snapshot snapshot.
   */
  def saveAsync(metadata: SnapshotMetadata, snapshot: Any): Future[Unit]

  /**
   * Plugin API: called after successful saving of a snapshot.
   *
   * @param metadata snapshot metadata.
   */
  def saved(metadata: SnapshotMetadata)

  /**
   * Plugin API: deletes the snapshot identified by `metadata`.
   *
   * @param metadata snapshot metadata.
   */

  def delete(metadata: SnapshotMetadata)

  /**
   * Plugin API: deletes all snapshots matching `criteria`.
   *
   * @param persistenceId processor id.
   * @param criteria selection criteria for deleting.
   */
  def delete(persistenceId: String, criteria: SnapshotSelectionCriteria)
  //#snapshot-store-plugin-api
}