code: public static boolean isFloat (@Nullable final String sStr)
    {
      return !Float.isNaN (parseFloat (sStr, Float.NaN));
    }
docs: Checks if the given string is a float string that can be converted to a
  double value.
  
  @param sStr
  The string to check. May be <code>null</code>.
  @return <code>true</code> if the value can be converted to a valid value