89 lines
3.3 KiB
Scala
89 lines
3.3 KiB
Scala
/*
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* Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
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*/
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package akka.persistence.query
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import java.util.concurrent.atomic.AtomicReference
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import akka.actor._
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import akka.event.Logging
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import scala.annotation.tailrec
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import scala.util.Failure
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/**
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* Persistence extension for queries.
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*/
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object PersistenceQuery extends ExtensionId[PersistenceQuery] with ExtensionIdProvider {
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/**
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* Java API.
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*/
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override def get(system: ActorSystem): PersistenceQuery = super.get(system)
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def createExtension(system: ExtendedActorSystem): PersistenceQuery = new PersistenceQuery(system)
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def lookup() = PersistenceQuery
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/** INTERNAL API. */
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private[persistence] case class PluginHolder(plugin: scaladsl.ReadJournal) extends Extension
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}
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class PersistenceQuery(system: ExtendedActorSystem) extends Extension {
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import PersistenceQuery._
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private val log = Logging(system, getClass)
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/** Discovered query plugins. */
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private val readJournalPluginExtensionIds = new AtomicReference[Map[String, ExtensionId[PluginHolder]]](Map.empty)
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/**
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* Returns the [[akka.persistence.query.scaladsl.ReadJournal]] specified by the given read journal configuration entry.
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*/
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@tailrec final def readJournalFor(readJournalPluginId: String): scaladsl.ReadJournal = {
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val configPath = readJournalPluginId
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val extensionIdMap = readJournalPluginExtensionIds.get
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extensionIdMap.get(configPath) match {
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case Some(extensionId) ⇒
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extensionId(system).plugin
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case None ⇒
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val extensionId = new ExtensionId[PluginHolder] {
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override def createExtension(system: ExtendedActorSystem): PluginHolder =
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PluginHolder(createPlugin(configPath))
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}
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readJournalPluginExtensionIds.compareAndSet(extensionIdMap, extensionIdMap.updated(configPath, extensionId))
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readJournalFor(readJournalPluginId) // Recursive invocation.
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}
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}
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/**
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* Java API
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*
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* Returns the [[akka.persistence.query.javadsl.ReadJournal]] specified by the given read journal configuration entry.
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*/
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final def getReadJournalFor(readJournalPluginId: String): javadsl.ReadJournal =
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new javadsl.ReadJournal(readJournalFor(readJournalPluginId))
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private def createPlugin(configPath: String): scaladsl.ReadJournal = {
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require(!isEmpty(configPath) && system.settings.config.hasPath(configPath),
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s"'reference.conf' is missing persistence read journal plugin config path: '${configPath}'")
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val pluginActorName = configPath
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val pluginConfig = system.settings.config.getConfig(configPath)
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val pluginClassName = pluginConfig.getString("class")
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log.debug(s"Create plugin: ${pluginActorName} ${pluginClassName}")
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val pluginClass = system.dynamicAccess.getClassFor[AnyRef](pluginClassName).get
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val plugin = system.dynamicAccess.createInstanceFor[scaladsl.ReadJournal](pluginClass, (classOf[ExtendedActorSystem], system) :: Nil)
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.orElse(system.dynamicAccess.createInstanceFor[scaladsl.ReadJournal](pluginClass, Nil))
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.recoverWith {
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case ex: Exception ⇒ Failure.apply(new IllegalArgumentException(s"Unable to create read journal plugin instance for path [$configPath], class [$pluginClassName]!", ex))
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}
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// TODO possibly apply event adapters here
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plugin.get
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}
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/** Check for default or missing identity. */
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private def isEmpty(text: String) = text == null || text.length == 0
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}
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