code: public static int getDistance (@Nullable final String sStr1, @Nullable final String sStr2)
    {
      final int nLen1 = StringHelper.getLength (sStr1);
      final int nLen2 = StringHelper.getLength (sStr2);
  
      if (nLen1 == 0)
        return nLen2;
      if (nLen2 == 0)
        return nLen1;
  
      return _getDistance111 (sStr1.toCharArray (), nLen1, sStr2.toCharArray (), nLen2);
    }
docs: Get the distance of the 2 strings, using the costs 1 for insertion,
  deletion and substitution.
  
  @param sStr1
  First string.
  @param sStr2
  second string.
  @return The Levenshtein distance.