public String getText() {
   if (HSSFErrorConstants.isValidCode(_errorCode)) {
     return HSSFErrorConstants.getText(_errorCode);
   }
   return "unknown error code (" + _errorCode + ")";
 }
 public String toFormulaString(FormulaRenderingWorkbook book) {
   return ExternSheetNameResolver.prependSheetName(
       book, field_1_index_extern_sheet, HSSFErrorConstants.getText(HSSFErrorConstants.ERROR_REF));
 }