// Timer.java

public class Timer {
   public Timer ()
   {  old     = 0.0D;
      time    = 0.0D;
      start   = 0.0D;
      current = 0.0D;
      running = false;
   }

   private double clock ()
   {  return (double)System.currentTimeMillis () / 1000D;  }

   public final double delta ()
   {  if (running) {
        double d  = clock ();
        double d1 = d - old;
         old = d;
         if (d1 < 0.0D)  d1 = 0.0D;
         return d1;
      }
      else {return 0.0D;}
   }

   public final double resolution ()  {return 0.001D;}

   public final void set (double d)
   {  current = d;
      start   = clock ();
      time    = start + d;
      old     = d - delta ();
   }

   public final void start ()
   {  if (!running) {
         start   = clock ();
         old     = clock ();
         running = true;
      }
   }

   public final void stop ()  {running = false;}

   public final double time ()
   {  if (running) {
        double d = clock ();
         if (d > time)  time = d;
         current = d - start;
      }
      return current;
   }

   private double  old, time, start, current;
   private boolean running;
}