package com.wzy.list;

import java.util.HashSet;

import java.util.Iterator;

import java.util.Set;

import java.util.TreeSet;

class Student1 implements Comparable{

    private Integer id;

    private String name;

    public Student1(String name,Integer id) {

        this.id = id;

        this.name = name;

    }

    @Override

    public String toString() {

        return "name:"+name+"; id:"+id;

    }

    @Override

    public int compareTo(Object o) {

        if(this.id > ((Student1)o).id) {

            return ;

        }else if(this.id < ((Student1)o).id) {

            return -;

        }else{

            return this.name.compareTo(((Student1)o).name);

        }

    }

}

class Student2{

    private Integer id;

    private String name;

    public Student2(String name,Integer id) {

        this.id = id;

        this.name = name;

    }

    @Override

    public int hashCode() {

        final int prime = ;

        int result = ;

        result = prime * result + ((id == null) ?  : id.hashCode());

        result = prime * result + ((name == null) ?  : name.hashCode());

        return result;

    }

    @Override

    public boolean equals(Object obj) {

        if (this == obj)

            return true;

        if (obj == null)

            return false;

        if (getClass() != obj.getClass())

            return false;

        Student2 other = (Student2) obj;

        if (id == null) {

            if (other.id != null)

                return false;

        } else if (!id.equals(other.id))

            return false;

        if (name == null) {

            if (other.name != null)

                return false;

        } else if (!name.equals(other.name))

            return false;

        return true;

    }

    @Override

    public String toString() {

        return "Student2 [id=" + id + ", name=" + name + "]";

    }    

}

public class Test02 {

    public static void main(String[] args) {

        /**

         * TreeSet和HashSet存入对象时，不会自动去重操作

         *

         * TreeSet去掉重复对象，基于Comparable接口实现

         * HashSet去掉重复对象，基于equals和hashCode实现

         * TreeSet可以对象排序，hashSet不可以

         *

         * 如果存入的不是new出来的对象，

         * 而是String或int类型，可以直接使用，不必实现上述操作

         * **/

        //TreeSet存入对象实例

        Set<Student1> stu1 = new TreeSet<Student1>();

        stu1.add(new Student1("aa",));

        stu1.add(new Student1("bb",));//id重复

        stu1.add(new Student1("dd",));

        stu1.add(new Student1("cc",));

        stu1.add(new Student1("aa",));//对象重复

        Iterator s = stu1.iterator();

        while(s.hasNext()) {

            System.out.println(s.next());

        }

        //HashSet存入对象实例

        Set<Student2> stu2 = new HashSet<Student2>();

        stu2.add(new Student2("aa",));

        stu2.add(new Student2("bb",));

        stu2.add(new Student2("cc",));

        stu2.add(new Student2("dd",));

        stu2.add(new Student2("ee",));

        stu2.add(new Student2("aa",));

        Iterator i = stu2.iterator();

        while(i.hasNext()) {

            System.out.println(i.next());

        }

        //TreeSet存入普通字符串

        Set set1 = new TreeSet();

        set1.add("a");

        set1.add("aa");

        set1.add("d");

        set1.add("b");

        set1.add("c");

        //[a, aa, b, c, d] TreeSet已经自动排序好了

        System.out.println(set1);

        //HashSet存入普通字符串

        Set set2 = new HashSet();

        set2.add("a");

        set2.add("aa");

        set2.add("d");

        set2.add("c");

        set2.add("b");

        //[aa, a, b, c, d] HashSet不会排序

        System.out.println(set2);

    }

}