java 작업기간 구하기에서 주말 여부 판단하기

/**
     * 지정일부터 작업전날까지.
     * <pre>작업 전날 구하기.
     * 1.그달 마지막일이 일요일이면 3일전까지
     * 2.그달 마지막일이 토요일이면 2일전까지
     * 3.그달 마지막일이 평일이면  1일전까지.
     * </pre>
     * @param currnetDate
     * @return
     */
    private boolean isWorkingDate(String currnetDate, int beginDay ) {
        String currentDate = currnetDate.replaceAll("-","");
        int year = Integer.parseInt(currentDate.substring(0,4));
        int month = Integer.parseInt(currentDate.substring(4,6));
        int day = Integer.parseInt(currentDate.substring(6,8));

        int endDay;

        Calendar cal = Calendar.getInstance();
        cal.set(year, month-1, day );
        int lastDayOfMonth = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
        cal.set(Calendar.DAY_OF_MONTH, lastDayOfMonth );
        int dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
        if( dayOfWeek == Calendar.SATURDAY ){
            endDay=lastDayOfMonth-2;
        }
        else if( dayOfWeek == Calendar.SUNDAY ){
            endDay=lastDayOfMonth-3;
        }
        else {
            endDay=lastDayOfMonth-1;
        }

        return day >= beginDay && day <= endDay;
    }