code: public void setDriftThreshold(double driftThreshold)
      {
          if(driftThreshold <= 0 || Double.isNaN(driftThreshold) || Double.isInfinite(driftThreshold))
              throw new IllegalArgumentException("Dritf threshold must be positive, not " + driftThreshold);
          this.driftThreshold = driftThreshold;
      }
docs: Sets the multiplier on the standard deviation that must be exceeded to
  recognize the change as a drift. <br>
  Increasing the drift threshold makes it take longer to start detecting
  a change, but reduces false positives.
  @param driftThreshold the positive multiplier threshold for detecting a
  drift