@Override
    public String validateData(String data) {
        String message = null;
        if(MarcWorxStringHelper.isEmpty(data) || data.length() != 6) {
            message = "A valid date in YYYYMM format is required";
        } else {
            String year = data.substring(0, 4);
            String month = data.substring(4, 6);
            if(MarcWorxStringHelper.contains(month, "-")) {
                month = "01";
            }
            try {
                int y = Integer.parseInt(year);
                int m = Integer.parseInt(month);
                if(y < 1000 || m < 1 || m > 12) {
                    message = "A valid date in YYYYMM format is required";
                }
            } catch (NumberFormatException ex) {
                message = "A valid date in YYYYMM format is required";
            }
        }
        return message;
    }