private void validateSize(RequestData requestData, Errors errors) {

        String sizeValue = requestData.getSize();
        if (StringUtils.isEmpty(sizeValue) || sizeValue.length() == 1) {
            errors.rejectValue("size", "size.invalid.length");
            return;
        }

        if (!sizeValue.startsWith(RequestData.PERCENTAGE_LITERAL) && !sizeValue.startsWith(RequestData.FULL_LITERAL)
                && !sizeValue.substring(0, 1)
                             .matches("\\d") && !sizeValue.startsWith(",") && !sizeValue.startsWith("!")) {
            errors.rejectValue("size", "size.invalid.start");
        }

    }