LambdaExpressionSortExample.java

package ch02;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class LambdaExpressionSortExample {
    static class Member {
        String name;
        int age;

        public Member(String name, int age) {
            this.name = name;
            this.age = age;
        }

        @Override
        public String toString() {
            return "Member{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }
    }

    public static void main(String[] args) {
        // 리스트에 데이터 삽입
        List<Member> members1 = new ArrayList<>();
        members1.add(new Member("윈터", 23));
        members1.add(new Member("카리나", 24));
        members1.add(new Member("닝닝", 22));

        // 정렬을 익명 클래스로 구현
        Collections.sort(members1, new Comparator<Member>() {
            @Override
            public int compare(Member o1, Member o2) {
                return o2.age - o1.age;
            }
        });

        System.out.println(members1);

        // ---

        List<Member> members2 = new ArrayList<>();
        members2.add(new Member("윈터", 23));
        members2.add(new Member("카리나", 24));
        members2.add(new Member("닝닝", 22));

        // 정렬을 람다 표현식으로 구현
        members2.sort((o1, o2) -> o2.age - o1.age);

        System.out.println(members2);
    }
}