src/Pure/Concurrent/counter.scala

--- a/src/Pure/Concurrent/counter.scala	Sat Oct 22 16:57:24 2011 +0200
+++ b/src/Pure/Concurrent/counter.scala	Sat Oct 22 19:00:03 2011 +0200
@@ -12,9 +12,10 @@
 object Counter
 {
   type ID = Long
+  def apply(): Counter = new Counter
 }
 
-class Counter
+class Counter private
 {
   private var count: Counter.ID = 0