public SkiPass getFirstHalfDaySkiPass(Date currentDate) {
        if (currentDate == null) {
            throw new IllegalArgumentException("Current date is null");
        }

        Calendar calendar = new GregorianCalendar();
        calendar.setTime(currentDate);
        calendar.set(Calendar.HOUR_OF_DAY, 9);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);

        Date activationDate = calendar.getTime();

        calendar.add(Calendar.HOUR_OF_DAY, 4);

        Date expirationDate = calendar.getTime();

        if (expirationDate.before(currentDate)) {
            return null;
        } else {
            return system.createSkiPass("HOURLY", activationDate,
                    expirationDate, 0);
        }
    }