de.sciss.synth.Model.scala Maven / Gradle / Ivy

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/*
 *  Model.scala
 *  (ScalaCollider)
 *
 *  Copyright (c) 2008-2012 Hanns Holger Rutz. All rights reserved.
 *
 *  This software is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either
 *  version 2, june 1991 of the License, or (at your option) any later version.
 *
 *  This software is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License (gpl.txt) along with this software; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *
 *  For further information, please contact Hanns Holger Rutz at
 *  [email protected]
 */

package de.sciss.synth

import collection.immutable.Queue

/**
 *    A Model implements the publish-subscribe pattern for
 *    generic (untyped) messages. Observers subscribe by
 *    calling addListener with an appropriate matcher
 *    function. When the Model dispatches a message, it
 *    invokes the apply method of all observers who are
 *    defined for the given message. Dispatching is
 *    synchronous, but exceptions are caught. 
 */
object Model {
   type Listener = PartialFunction[ AnyRef, Unit ]
   object EmptyListener extends Listener {
      def isDefinedAt( v: AnyRef ) = false
      def apply( v: AnyRef ) { throw new MatchError( v )}
   }
}
trait Model {
   import Model._

   private var listeners   = Queue.empty[ Listener ]
   private val sync        = new AnyRef

   protected def dispatch( change: AnyRef ) {
      listeners foreach { l =>
         val t1 = System.currentTimeMillis
         try {
            if( l.isDefinedAt( change )) l( change )
         } catch {
            case e: Throwable => e.printStackTrace() // catch, but print
         } finally {
val t2 = System.currentTimeMillis
if( (t2 - t1) > 2000 ) println( "" + new java.util.Date() + " WOW listener took long (" + (t2-t1) + ") : " +
   change + " -> " + l )
         }
      }
   }

   def addListener( l: Listener ) : Listener = {
      sync.synchronized {
         listeners = listeners.enqueue( l )
      }
      l
   }

   def removeListener( l: Listener ) : Listener = {
      sync.synchronized {
         // multi set diff just removes one instance --
         // observers could register more than once if they want
         listeners = listeners.diff( List( l ))
      }
      l
   }
}