Scala example source code file (SingleThreadedScheduler.scala)

This example Scala source code file (SingleThreadedScheduler.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, actors, collection, for, guide, ischeduler, migration, runnable, singlethreadedscheduler, trackedreactor, unit, use

The SingleThreadedScheduler.scala Scala example source code

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


package scala.actors
package scheduler

import scala.collection.mutable

/**
 * This scheduler executes actor tasks on the current thread.
 *
 * @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")
class SingleThreadedScheduler extends IScheduler {

  private val tasks = new mutable.Queue[Runnable]

  /** The maximum number of nested tasks that are run
   *  without unwinding the call stack.
   */
  protected val maxNesting = 10

  private var curNest = 0
  private var isShutdown = false

  def execute(task: Runnable) {
    if (curNest < maxNesting) {
      curNest += 1
      task.run()
    } else {
      curNest = 0
      tasks += task
    }
  }

  def execute(fun: => Unit): Unit =
    execute(new Runnable {
      def run() { fun }
    })

  def shutdown() {
    isShutdown = false
    while (!tasks.isEmpty) {
      val task = tasks.dequeue()
      task.run()
    }
    isShutdown = true
  }

  def newActor(actor: TrackedReactor) {}
  def terminated(actor: TrackedReactor) {}

  // TODO: run termination handlers at end of shutdown.
  def onTerminate(actor: TrackedReactor)(f: => Unit) {}

  def isActive =
    !isShutdown

  def managedBlock(blocker: scala.concurrent.ManagedBlocker) {
    blocker.block()
  }
}