Java TreeSet : I want to do duplicate check by number and sort by string

Question

    import java.util.Comparator;
    public class Member implements Comparable<Member>{
    private int id;
    private String name;
    
    public Member() {}
    
    public Member(int id, String name) {
        this.id = id;
        this.name = name;
    }
    
    public int getID() {
        return this.id;
    }
    public String getName() {
        return this.name;
    }
    
    @Override
    public String toString() {
        return this.id + " : " + this.name;
    }

    @Override
    public int hashCode() {
        return this.id;
    }
    
    @Override
    public boolean equals(Object obj) {
        if(obj instanceof Member) {
            Member m = (Member)obj;
            
            if(this.getID() == m.getID()) {
                return true;
            }
        }
        return false;
    }
    
    @Override
    public int compareTo(Member m) {
        return this.name.compareTo(m.getName());
    }
}

================================================

    import java.util.TreeSet;
    public class TreeSetTest {
    public static void main(String[] args) {
        TreeSet<Member> ts = new TreeSet<Member>();
        
        ts.add(new Member(1007, "LimEunHa"));
        ts.add(new Member(1012, "JangBoYoung"));
        ts.add(new Member(1002, "AhnJinWoo"));
        ts.add(new Member(1001, "KimSiYeon"));
        ts.add(new Member(1007, "EunHa"));
        ts.add(new Member(1002, "JinWoo"));
        
        for(Member m : ts) {
            System.out.println(m);
        }
    }
}

=============================================

Result<br/>
1002:AhgnJinWoo<br/>
1007:EunHa<br/>
1012:JangBoYoung<br/>
1002:JinWoo<br/>
1001:KimSiYeoun<br/>
1007:LimEunHa<br/>

This code performs sorting, but allows duplication. I don't want to allow duplicates. I want sorting by String(name), duplication check by int(id).

Answer 1

You can use ArrayList to store Member objects

        List<Member> ls = new ArrayList<Member>();

        ls.add(new Member(1007, "LimEunHa"));
        ls.add(new Member(1012, "JangBoYoung"));
        ls.add(new Member(1002, "AhnJinWoo"));
        ls.add(new Member(1001, "KimSiYeon"));
        ls.add(new Member(1007, "EunHa"));
        ls.add(new Member(1002, "JinWoo"));

get the distinct members from stream of member list and sorted

        ls = ls.stream().distinct().sorted().collect(Collectors.toList());
 
        ls.forEach(System.out::println);

Output:

1002 : AhnJinWoo
1012 : JangBoYoung
1001 : KimSiYeon
1007 : LimEunHa