#1692 - Adding config option for making the Scheduler daemonic

akka-actor-tests/src/test/scala/akka/config/ConfigSpec.scala

@@ -36,9 +36,18 @@ class ConfigSpec extends AkkaSpec(ConfigFactory.defaultReference) {
       getMilliseconds("akka.actor.default-dispatcher.shutdown-timeout") must equal(1 * 1000)
       getInt("akka.actor.default-dispatcher.throughput") must equal(5)
       getMilliseconds("akka.actor.default-dispatcher.throughput-deadline-time") must equal(0)
+
       getBoolean("akka.actor.serialize-messages") must equal(false)
       settings.SerializeAllMessages must equal(false)
 
+      getInt("akka.scheduler.ticksPerWheel") must equal(512)
+      settings.SchedulerTicksPerWheel must equal(512)
+
+      getMilliseconds("akka.scheduler.tickDuration") must equal(100)
+      settings.SchedulerTickDuration must equal(100 millis)
+
+      getBoolean("akka.scheduler.daemonic") must equal(true)
+      settings.SchedulerDaemonicity must equal(true)
     }
   }
 }

akka-actor/src/main/resources/reference.conf

@@ -271,5 +271,6 @@ akka {
     # For more information see: http://www.jboss.org/netty/
     tickDuration = 100ms
     ticksPerWheel = 512
+    daemonic = on
   }
 }

akka-actor/src/main/scala/akka/actor/ActorSystem.scala

@@ -96,6 +96,7 @@ object ActorSystem {
 
     final val SchedulerTickDuration = Duration(getMilliseconds("akka.scheduler.tickDuration"), MILLISECONDS)
     final val SchedulerTicksPerWheel = getInt("akka.scheduler.ticksPerWheel")
+    final val SchedulerDaemonicity = getBoolean("akka.scheduler.daemonic")
 
     if (ConfigVersion != Version)
       throw new ConfigurationException("Akka JAR version [" + Version + "] does not match the provided config version [" + ConfigVersion + "]")
@@ -408,18 +409,18 @@ class ActorSystemImpl(val name: String, applicationConfig: Config) extends Actor
    * executed upon close(), the task may execute before its timeout.
    */
   protected def createScheduler(): Scheduler = {
-    val threadFactory = new MonitorableThreadFactory("DefaultScheduler")
-    val hwt = new HashedWheelTimer(log, threadFactory, settings.SchedulerTickDuration, settings.SchedulerTicksPerWheel)
+    val hwt = new HashedWheelTimer(log,
+      new MonitorableThreadFactory("DefaultScheduler", settings.SchedulerDaemonicity),
+      settings.SchedulerTickDuration,
+      settings.SchedulerTicksPerWheel)
     // note that dispatcher is by-name parameter in DefaultScheduler constructor,
     // because dispatcher is not initialized when the scheduler is created
-    def safeDispatcher = {
-      if (dispatcher eq null) {
+    def safeDispatcher = dispatcher match {
+      case null ⇒
         val exc = new IllegalStateException("Scheduler is using dispatcher before it has been initialized")
         log.error(exc, exc.getMessage)
         throw exc
-      } else {
-        dispatcher
-      }
+      case dispatcher ⇒ dispatcher
     }
     new DefaultScheduler(hwt, log, safeDispatcher)
   }

akka-actor/src/main/scala/akka/actor/Scheduler.scala

@@ -123,7 +123,9 @@ trait Cancellable {
  * if it does not enqueue a task. Once a task is queued, it MUST be executed or
  * returned from stop().
  */
-class DefaultScheduler(hashedWheelTimer: HashedWheelTimer, log: LoggingAdapter, dispatcher: ⇒ MessageDispatcher) extends Scheduler with Closeable {
+class DefaultScheduler(hashedWheelTimer: HashedWheelTimer,
+                       log: LoggingAdapter,
+                       dispatcher: ⇒ MessageDispatcher) extends Scheduler with Closeable {
 
   def schedule(initialDelay: Duration, delay: Duration, receiver: ActorRef, message: Any): Cancellable = {
     val continuousCancellable = new ContinuousCancellable