code: public void setSmoothing(double smoothing)
      {
          if (smoothing <= 0 || smoothing > 1 || Double.isNaN(smoothing))
              throw new IllegalArgumentException("Smoothing must be in (0, 1], not " + smoothing);
          this.smoothing = smoothing;
      }
docs: Sets the smoothing parameter value to use. Must be in the range (0, 1].
  Changing this value will impact how quickly the statistics adapt to
  changes, with larger values increasing rate of change and smaller values
  decreasing it.
  
  @param smoothing the smoothing value to use