Comparable와 Comparator 인터페이스 오버라이딩(4)

 

import java.util.*;

class Student2 {
 String name;
 int ban;
 int no;
 int kor, eng, math;

 public Student2(String name, int ban, int no, int kor, int eng, int math) {
  this.name = name;
  this.ban = ban;
  this.no = no;
  this.kor = kor;
  this.eng = eng;
  this.math = math;
 }

 int getTotal() {
  return kor + eng + math;
 }

 float getAverage() {
  return (int) (((getTotal() / 3f) * 10 + 0.5) / 10f);
 }

 public String toString() {
  return name + "," + ban + "," + no + "," + eng + "," + math + ","
    + getTotal() + "," + getAverage();
 }

}

class BanNoAscending implements Comparator {
 public int compare(Object o1, Object o2) {
  if(o1 instanceof Student2 && o2 instanceof Student2) {
   Student2 s1 = (Student2)o1;
   Student2 s2 = (Student2)o2;
   int result = s1.ban - s2.ban;
   if(result==0) { // 반이 같으면, 번호를 비교한다.
    return s1.no - s2.no;
   }
   return result;
  }
  return -1;
 }
}

public class Exercise11_7 {
 public static void main(String[] args) {
  ArrayList list = new ArrayList();
  list.add(new Student2("이자바", 2, 1, 70, 90, 70));
  list.add(new Student2("안자바", 2, 2, 60, 100, 80));
  list.add(new Student2("홍길동", 1, 3, 100, 100, 100));
  list.add(new Student2("남궁성", 1, 1, 90, 70, 80));
  list.add(new Student2("김자바", 1, 2, 80, 80, 90));

  Collections.sort(list, new BanNoAscending());
  Iterator it = list.iterator();

  while (it.hasNext())
   System.out.println(it.next());
 }

}