code: public static String getConvertedStringValue(FacesContext context,
              UIComponent component, Converter converter, SelectItem selectItem)
      {
          return getConvertedStringValue(context, component, converter,
                  selectItem.getValue());
      }
docs: Convenient utility method that returns the currently given SelectItem value
  as String, using the given converter.
  Especially usefull for dealing with primitive types.