每日一题（17）

public class Point {
    protected  int x,y;
    private  String name;

    Point(int x,int y){
        this.x = x;
        this.y = y;
        //3.此处调用子类的makeName方法
        //因为该方法被子类方法覆盖了
        this.name = makeName();
    }

    protected  String makeName(){
        return "["+ x + "," + y +"]";
    }

    @Override
    public String toString(){
        return name;
    }

}

class ColorPoint extends Point{
     private String color;

     ColorPoint(int x, int y, String color){
         //2.调用父类的构造方法
         super(x,y);
         this.color = color;
     }

     @Override
     protected String makeName(){
         //4.在ColorPoint构造函数未执行完时,color未null
         //所以返回[4,2]:null
         return super.makeName() + ":" + color;
     }

     public static void main(String[] args){
         //1.调用子类的构造方法
         System.out.println(new ColorPoint(4, 2, "blue"));
     }
}

public class Name {
    private final  String first, last;

    public Name(String first, String last){
        this.first = first;
        this.last = last;
    }

    @Override
    public  boolean equals(Object o){
        if(o instanceof Name){
            return  false;
        }
        Name n = (Name)o;
        return n.first.equals(first) && n.last.equals(last);
    }

    public static  void main(String[] args){
        Set<Name> s = new HashSet<>();
        s.add(new Name("Mickey", "Mouse"));
        System.out.println(
                s.contains(new Name("Mickey", "Mouse")));
    }
}