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

This example Akka source code file (CachingConfig.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

akka, boolean, cachingconfig, config, configresolveoptions, dispatch, pathentry, string, stringpathentry, timeunit, try, utilities, valuepathentry

The CachingConfig.scala Akka example source code

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

package akka.dispatch

import com.typesafe.config._
import java.util.concurrent.ConcurrentHashMap
import scala.util.{ Failure, Success, Try }
import java.util.concurrent.TimeUnit

/**
 * INTERNAL API
 */
private[akka] object CachingConfig {
  val emptyConfig = ConfigFactory.empty()

  sealed abstract trait PathEntry {
    val valid: Boolean
    val exists: Boolean
    val config: Config
  }
  final case class ValuePathEntry(valid: Boolean, exists: Boolean, config: Config = emptyConfig) extends PathEntry
  final case class StringPathEntry(valid: Boolean, exists: Boolean, config: Config, value: String) extends PathEntry

  val invalidPathEntry = ValuePathEntry(false, true)
  val nonExistingPathEntry = ValuePathEntry(true, false)
  val emptyPathEntry = ValuePathEntry(true, true)
}

/**
 * INTERNAL API
 *
 * A CachingConfig is a Config that wraps another Config and is used to cache path lookup and string
 * retrieval, which we happen to do a lot in some critical paths of the actor creation and mailbox
 * selection code.
 *
 * All other Config operations are delegated to the wrapped Config.
 */
private[akka] class CachingConfig(_config: Config) extends Config {

  import CachingConfig._

  private val (config: Config, entryMap: ConcurrentHashMap[String, PathEntry]) = _config match {
    case cc: CachingConfig ⇒ (cc.config, cc.entryMap)
    case _                 ⇒ (_config, new ConcurrentHashMap[String, PathEntry])
  }

  private def getPathEntry(path: String): PathEntry = entryMap.get(path) match {
    case null ⇒
      val ne = Try { config.hasPath(path) } match {
        case Failure(e)     ⇒ invalidPathEntry
        case Success(false) ⇒ nonExistingPathEntry
        case _ ⇒
          Try { config.getValue(path) } match {
            case Failure(e) ⇒
              emptyPathEntry
            case Success(v) ⇒
              if (v.valueType() == ConfigValueType.STRING)
                StringPathEntry(true, true, v.atKey("cached"), v.unwrapped().asInstanceOf[String])
              else
                ValuePathEntry(true, true, v.atKey("cached"))
          }
      }

      entryMap.putIfAbsent(path, ne) match {
        case null ⇒ ne
        case e    ⇒ e
      }

    case e ⇒ e
  }

  def checkValid(reference: Config, restrictToPaths: String*) {
    config.checkValid(reference, restrictToPaths: _*)
  }

  def root() = config.root()

  def origin() = config.origin()

  def withFallback(other: ConfigMergeable) = new CachingConfig(config.withFallback(other))

  def resolve() = resolve(ConfigResolveOptions.defaults())

  def resolve(options: ConfigResolveOptions) = {
    val resolved = config.resolve(options)
    if (resolved eq config) this
    else new CachingConfig(resolved)
  }

  def hasPath(path: String) = {
    val entry = getPathEntry(path)
    if (entry.valid)
      entry.exists
    else // run the real code to get proper exceptions
      config.hasPath(path)
  }

  def isEmpty = config.isEmpty

  def entrySet() = config.entrySet()

  def getBoolean(path: String) = config.getBoolean(path)

  def getNumber(path: String) = config.getNumber(path)

  def getInt(path: String) = config.getInt(path)

  def getLong(path: String) = config.getLong(path)

  def getDouble(path: String) = config.getDouble(path)

  def getString(path: String) = {
    getPathEntry(path) match {
      case StringPathEntry(_, _, _, string) ⇒
        string
      case e ⇒ e.config.getString("cached")
    }
  }

  def getObject(path: String) = config.getObject(path)

  def getConfig(path: String) = config.getConfig(path)

  def getAnyRef(path: String) = config.getAnyRef(path)

  def getValue(path: String) = config.getValue(path)

  def getBytes(path: String) = config.getBytes(path)

  def getMilliseconds(path: String) = config.getMilliseconds(path)

  def getNanoseconds(path: String) = config.getNanoseconds(path)

  def getList(path: String) = config.getList(path)

  def getBooleanList(path: String) = config.getBooleanList(path)

  def getNumberList(path: String) = config.getNumberList(path)

  def getIntList(path: String) = config.getIntList(path)

  def getLongList(path: String) = config.getLongList(path)

  def getDoubleList(path: String) = config.getDoubleList(path)

  def getStringList(path: String) = config.getStringList(path)

  def getObjectList(path: String) = config.getObjectList(path)

  def getConfigList(path: String) = config.getConfigList(path)

  def getAnyRefList(path: String) = config.getAnyRefList(path)

  def getBytesList(path: String) = config.getBytesList(path)

  def getMillisecondsList(path: String) = config.getMillisecondsList(path)

  def getNanosecondsList(path: String) = config.getNanosecondsList(path)

  def withOnlyPath(path: String) = new CachingConfig(config.withOnlyPath(path))

  def withoutPath(path: String) = new CachingConfig(config.withoutPath(path))

  def atPath(path: String) = new CachingConfig(config.atPath(path))

  def atKey(key: String) = new CachingConfig(config.atKey(key))

  def withValue(path: String, value: ConfigValue) = new CachingConfig(config.withValue(path, value))

  def getDuration(path: String, unit: TimeUnit) = config.getDuration(path, unit)

  def getDurationList(path: String, unit: TimeUnit) = config.getDurationList(path, unit)

  def isResolved() = config.isResolved()

  def resolveWith(source: Config, options: ConfigResolveOptions) = config.resolveWith(source, options)

  def resolveWith(source: Config) = config.resolveWith(source)
}