Scala example source code file (prodcons.scala)

This example Scala source code file (prodcons.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

array, array, console, console, int, int, sharedbuffer, sharedbuffer, syncvar

The Scala prodcons.scala source code

/* The Computer Language Shootout 
   http://shootout.alioth.debian.org/
   contributed by Isaac Gouy (Scala novice)
*/

import concurrent.SyncVar;
import concurrent.ops._;

object prodcons {
   def main(args: Array[String]) = {
      val n = toPositiveInt(args);
      val buffer = new SharedBuffer();
      var p = 0;
      var c = 0;
      val cDone = new SyncVar[Boolean];

      spawn { 
         while(p<n) { p=p+1; buffer put(p); }
      }

      spawn { 
         var v: Int = _;
         while(c<n) { c=c+1; v = buffer.get; }
         cDone set true;
      }

      cDone.get;
      Console println(p + " " + c); 
   }


   private def toPositiveInt(s: Array[String]) = {
      val i = 
         try { Integer.parseInt(s(0)); } 
         catch { case _ => 1 }
      if (i>0) i; else 1;
   }
}


private class SharedBuffer() {
   var contents: Int = _;
   var available = false;

   def get = synchronized {
      while (available == false) wait();
      available = false;
         // Console println("\t" + "get " + contents);
      notifyAll();
      contents
   }

   def put(value: Int) = synchronized {
      while (available == true) wait();
      contents = value;
      available = true;
         // Console println("put " + value);
      notifyAll();
   }
}