Scala example source code file (RemoteActor.scala)

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

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

Scala tags/keywords

actor, classloader, for, guide, int, netkernel, node, none, some, symbol, use

The RemoteActor.scala Scala example source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2005-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */



package scala.actors
package remote


/**
 *  This object provides methods for creating, registering, and
 *  selecting remotely accessible actors.
 *
 *  A remote actor is typically created like this:
 *  {{{
 *  actor {
 *    alive(9010)
 *    register('myName, self)
 *
 *    // behavior
 *  }
 *  }}}
 *  It can be accessed by an actor running on a (possibly)
 *  different node by selecting it in the following way:
 *  {{{
 *  actor {
 *    // ...
 *    val c = select(Node("127.0.0.1", 9010), 'myName)
 *    c ! msg
 *    // ...
 *  }
 *  }}}
 *
 * @author Philipp Haller
 */
@deprecated("Use the akka.actor package instead. For migration from the scala.actors package refer to the Actors Migration Guide.", "2.11.0")
object RemoteActor {

  private val kernels = new scala.collection.mutable.HashMap[InternalActor, NetKernel]

  /* If set to <code>null</code> (default), the default class loader
   * of <code>java.io.ObjectInputStream</code> is used for deserializing
   * objects sent as messages.
   */
  private var cl: ClassLoader = null

  def classLoader: ClassLoader = cl
  def classLoader_=(x: ClassLoader) { cl = x }

  /**
   * Makes <code>self</code> remotely accessible on TCP port
   * <code>port</code>.
   */
  def alive(port: Int): Unit = synchronized {
    createNetKernelOnPort(port)
  }

  private def createNetKernelOnPort(port: Int): NetKernel = {
    val serv = TcpService(port, cl)
    val kern = serv.kernel
    val s = Actor.self(Scheduler)
    kernels(s) = kern

    s.onTerminate {
      Debug.info("alive actor "+s+" terminated")
      // remove mapping for `s`
      kernels -= s
      // terminate `kern` when it does
      // not appear as value any more
      if (!kernels.valuesIterator.contains(kern)) {
        Debug.info("terminating "+kern)
        // terminate NetKernel
        kern.terminate()
      }
    }

    kern
  }

  /**
   * Registers <code>a</code> under <code>name</code> on this
   * node.
   */
  def register(name: Symbol, a: Actor): Unit = synchronized {
    val kernel = kernels.get(Actor.self(Scheduler)) match {
      case None =>
        val serv = TcpService(TcpService.generatePort, cl)
        kernels(Actor.self(Scheduler)) = serv.kernel
        serv.kernel
      case Some(k) =>
        k
    }
    kernel.register(name, a)
  }

  private def selfKernel = kernels.get(Actor.self(Scheduler)) match {
    case None =>
      // establish remotely accessible
      // return path (sender)
      createNetKernelOnPort(TcpService.generatePort)
    case Some(k) =>
      k
  }

  /**
   * Returns (a proxy for) the actor registered under
   * <code>name</code> on <code>node</code>.
   */
  def select(node: Node, sym: Symbol): AbstractActor = synchronized {
    selfKernel.getOrCreateProxy(node, sym)
  }

  private[remote] def someNetKernel: NetKernel =
    kernels.valuesIterator.next
}


/**
 * This class represents a machine node on a TCP network.
 *
 * @param address the host name, or <code>null</code> for the loopback address.
 * @param port    the port number.
 *
 * @author Philipp Haller
 */
@deprecated("Use the akka.actor package instead. For migration from the scala.actors package refer to the Actors Migration Guide.", "2.11.0")
case class Node(address: String, port: Int)