public class ADate implements AcademicDate {
    private int week;
    private int day;
    public int getWeek() { return week;}
    public int getDay() { return day;}
    public ADate(int w, int d) { set(w,d); }
    public boolean setWeek(int w) {
        week = w;
        return true;
    }
    public boolean setDay(int d) {
        if ( d < 0 || d > 6 ) return false;
        day = d;
        return true;
    }
    public boolean set(int w, int d) {
        // note that this relies on knowledge of how the other routines
        // behave, in particular that setWeek will never fail.
        return setDay(d) && setWeek(w);
    }
}