code: protected int convertText(String text, Locale locale) {
          try {
              return Integer.parseInt(text);
          } catch (NumberFormatException ex) {
              throw new IllegalFieldValueException(getType(), text);
          }
      }
docs: Convert the specified text and locale into a value.
  
  @param text  the text to convert
  @param locale  the locale to convert using
  @return the value extracted from the text
  @throws IllegalArgumentException if the text is invalid