Scala example source code file (TerminationService.scala)

This example Scala source code file (TerminationService.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, check_freq, interruptedexception, ischeduler, quitcontrol, terminationmonitor, terminationservice, thread, unit

The TerminationService.scala Scala example source code

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


package scala.actors
package scheduler

import java.lang.{Thread, InterruptedException}

/**
 * The <code>TerminationService</code> class starts a new thread
 * that is used to check regularly if the scheduler can be
 * shut down, because all started actors are known to
 * have terminated.
 *
 * @author Philipp Haller
 */
private[scheduler] trait TerminationService extends TerminationMonitor {
  _: Thread with IScheduler =>

  private var terminating = false

  /** Indicates whether the scheduler should terminate when all
   *  actors have terminated.
   */
  protected val terminate = true

  protected val CHECK_FREQ = 50

  def onShutdown(): Unit

  override def run() {
    try {
      while (true) {
        this.synchronized {
          try {
            wait(CHECK_FREQ.toLong)
          } catch {
            case _: InterruptedException =>
          }

          if (terminating || (terminate && allActorsTerminated))
            throw new QuitControl

          gc()
        }
      }
    } catch {
      case _: QuitControl =>
        Debug.info(this+": initiating shutdown...")
        // invoke shutdown hook
        onShutdown()
        // allow thread to exit
    }
  }

  /** Shuts down the scheduler.
   */
  def shutdown(): Unit = synchronized {
    terminating = true
  }

}