Scala example source code file (Alarms.scala)

This example Scala source code file (Alarms.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

alarmer, alarmer, alarmeraction, alarmeraction, cancelling, i've, i've, int, interruptedexception, now, option, simplealarm, unit, unit, util

The Scala Alarms.scala source code

/* NEST (New Scala Test)
 * Copyright 2007-2011 LAMP/EPFL
 * @author Paul Phillips
 */

package scala.tools
package partest

import java.util.{ Timer, TimerTask }

trait Alarms {
  self: Universe =>
  
  def interruptMeIn[T](debugMsg: String, seconds: Int)(body: => T): Option[T] = {
    val thisThread  = currentThread
    val alarm       = new SimpleAlarm(seconds * 1000) set thisThread.interrupt()
    debug("interruptMeIn(%d) '%s'".format(seconds, debugMsg))
    
    try     { Some(body) }
    catch   { case _: InterruptedException => debug("Received interrupted exception.") ; None }
    finally { debug("Cancelling interruptMeIn '%s'" format debugMsg) ; alarm.cancel() ; Thread.interrupted() }
  }

  case class AlarmerAction(secs: Int, action: () => Unit) extends Runnable {
    override def run() = action()
  }
  
  /** Set any number of alarms up with tuples of the form:
   *    seconds to alarm -> Function0[Unit] to execute
   */
  class Alarmer(alarms: AlarmerAction*) {
    import java.util.concurrent._
    
    val exec = Executors.newSingleThreadScheduledExecutor()
    alarms foreach (x => exec.schedule(x, x.secs, TimeUnit.SECONDS))
    exec.shutdown()

    def cancelAll() = exec.shutdownNow()
  }
  
  class SimpleAlarm(timeout: Long) {
    private val alarm = new Timer

    /** Start a timer, running the given body if it goes off.
     */
    def set(body: => Unit) = returning(new TimerTask { def run() = body })(alarm.schedule(_, timeout))
    
    /** Cancel the timer.
     */
    def cancel() = alarm.cancel()
  }
  
  trait TestAlarms {
    test: TestEntity =>
    
    private def warning1 = AlarmerAction(testWarning, () => warning(
      """|I've been waiting %s seconds for this to complete:
         |  %s
         |It may be stuck, or if not, it should be broken into smaller tests.
         |""".stripMargin.format(testWarning, test))
    )
    private def warning2 = AlarmerAction(testWarning * 2, () => warning(
      """|Now I've been waiting %s seconds for this to complete:
         |  %s
         |If partest seems hung it would be a good place to look.
         |""".stripMargin.format(testWarning * 2, test))
    )
    
    def startAlarms(onTimeout: => Unit) =
      if (isNoAlarms) new Alarmer() // for alarm debugging
      else new Alarmer(Seq(warning1, warning2, AlarmerAction(testTimeout, () => onTimeout)): _*)
  }
  
  // Thread.setDefaultUncaughtExceptionHandler(new UncaughtException)
  // class UncaughtException extends Thread.UncaughtExceptionHandler {
  //   def uncaughtException(t: Thread, e: Throwable) {
  //     Console.println("Uncaught in %s: %s".format(t, e))
  //   }
  // }
  // 
  // lazy val logger = File("/tmp/partest.log").bufferedWriter()
  // def flog(msg: String) = logger synchronized {
  //   logger write (msg + "\n")
  //   logger.flush()
  // }
}