code: public static void setXSLTVersion(String s) {
          try {
              Number n = NumberFormat.getInstance(Locale.US).parse(s);
              if (n.doubleValue() < 0) {
                  throw new ConfigurationException(s + " doesn't reperesent a"
                                                   + " positive number.");
              }
          } catch (ParseException e) {
              throw new ConfigurationException(e);
          }
          xsltVersion = s;
      }
docs: Sets the XSLT version to set on stylesheets used internally.
  
  <p>Defaults to "1.0".</p>
  
  @throws ConfigurationException if the argument cannot be parsed
  as a positive number.