public class Student implements Comparable{
    private String fullName;
    private Date registrationDate;

public Person(String fullName){
    this.fullName = fullName;
}

public String getFullName() {
    return fullName;
}

public void setFullName(String fullName) {
    this.fullName = fullName;
}

public Date getRegistrationDate() {
        return registrationDate;
    }
    public void setRegistrationDate(Date registrationDate) {
        this.registrationDate = registrationDate;
    }

@Override
    public int compareTo(Object obj) {
        Person person = (Person) obj;

        if(person instanceof Staff){
            return 1;
        }else if(person instanceof Student){
            return -1;
        }
        else if(getRegistrationDate().before(person.getRegistrationDate())){
            return 1;
        }else if(getRegistrationDate().after(person.getRegistrationDate())){
            return -1;
        }
        return 0;
    }
}

public class Staff extends Person{
    public Staff(String fullName){
        this.fullName = fullName;
     }
}

public class Student extends Member{
    public Student(String fullName){
        this.fullName = fullName;
     }
}

public class School {

    public static void main(String args[]) {

        //list of students
        Student student1 = new Student("John Kent");
        Date dateStudent1Joined = new GregorianCalendar(2014, Calendar.JULY, 1).getTime();
        student1.setRegistrationDate(dateStudent1Joined);

        Student student2 = new Student("Peter Tush");
        Date dateStudent2Joined = new GregorianCalendar(2014, Calendar.JULY, 2).getTime();
        student2.setRegistrationDate(dateStudent2Joined);

        Student student3 = new Student("Mike Monroe");
        Date dateStudent3Joined = new GregorianCalendar(2014, Calendar.JULY, 3).getTime();
        student3.setRegistrationDate(dateStudent3Joined);

        Student student4 = new Student("Tom Johnson");
        Date dateStudent4Joined = new GregorianCalendar(2014, Calendar.JULY, 4).getTime();
        student4.setRegistrationDate(dateStudent4Joined);

        Student student5 = new Student("Tony Spencer");
        Date dateStudent5Joined = new GregorianCalendar(2014, Calendar.JULY, 5).getTime();
        student5.setRegistrationDate(dateStudent5Joined);

        //list of staff
        Staff staff1 = new Staff("Luke Clint");
        Date dateStaff1Joined = new GregorianCalendar(2014, Calendar.JULY, 6).getTime();
        staff1.setRegistrationDate(dateStaff1Joined);

        Staff staff2 = new Staff("Ron West");
        Date dateStaff2Joined = new GregorianCalendar(2014, Calendar.JULY, 7).getTime();
        staff2.setRegistrationDate(dateStaff2Joined);

        Staff staff3 = new Staff("Jim Gary");
        Date dateStaff3Joined = new GregorianCalendar(2014, Calendar.JULY, 8).getTime();
        staff3.setRegistrationDate(dateStaff3Joined);


        //create a queue data structure to hold Persons in school
        PriorityQueue<Person> schoolQueue = new PriorityQueue<Person>();
        //add students to queue
        schoolQueue.offer(student1);
        schoolQueue.offer(student2);
        schoolQueue.offer(student3);
        schoolQueue.offer(student4);
        schoolQueue.offer(student5);
        //add staff to queue
        schoolQueue.offer(staff1);
        schoolQueue.offer(staff2);
        schoolQueue.offer(staff3);

        //print names of people in queue
        for(Member member : clubQueue){
            String memberName = member.getFullName();
            System.out.println(memberName);
        }

    }
}

@Override
        public int compareTo(Object obj) {
            Person person = (Person) obj;

            if(person instanceof Staff){
                return 1;
            }else if(person instanceof Student){
                return -1;
            }
            else if(getRegistrationDate().before(person.getRegistrationDate())){
                return 1;
            }else if(getRegistrationDate().after(person.getRegistrationDate())){
                return -1;
            }
            return 0;
        }