Person
public abstract class Person {
  //提供一个方法，让访问者可以访问
  public abstract void accept(Action action);
}

//说明
//1. 这里我们使用到了双分派, 即首先在客户端程序中，将具体状态作为参数传递Woman中(第一次分派)
//2. 然后Woman 类调用作为参数的 "具体方法" 中方法getWomanResult, 同时将自己(this)作为参数
//   传入，完成第二次的分派
public class Woman extends Person{
  @Override
  public void accept(Action action) {
  // TODO Auto-generated method stub
  action.getWomanResult(this);
  }
}

public class Man extends Person {
  @Override
  public void accept(Action action) {
  // TODO Auto-generated method stub
  action.getManResult(this);
  }
}

public abstract class Action {
  //得到男性 的测评
  public abstract void getManResult(Man man);
  //得到女的 测评
  public abstract void getWomanResult(Woman woman);
}

public class Success extends Action {
  @Override
  public void getManResult(Man man) {
  // TODO Auto-generated method stub
  System.out.println(" 男人给的评价该歌手很成功 !");
  }
  @Override
  public void getWomanResult(Woman woman) {
  // TODO Auto-generated method stub
  System.out.println(" 女人给的评价该歌手很成功 !");
  }
}

public class Fail extends Action {
  @Override
  public void getManResult(Man man) {
  // TODO Auto-generated method stub
  System.out.println(" 男人给的评价该歌手失败 !");
  }
  @Override
  public void getWomanResult(Woman woman) {
  // TODO Auto-generated method stub
  System.out.println(" 女人给的评价该歌手失败 !");
  }
}

public class Wait extends Action {
  @Override
  public void getManResult(Man man) {
  // TODO Auto-generated method stub
  System.out.println(" 男人给的评价是该歌手待定 ..");
  }
  @Override
  public void getWomanResult(Woman woman) {
  // TODO Auto-generated method stub
  System.out.println(" 女人给的评价是该歌手待定 ..");
  }
}

//数据结构，管理很多人（Man , Woman）
public class ObjectStructure {
  //维护了一个集合
  private List<Person> persons = new LinkedList<>();
  //增加到list
  public void attach(Person p) {
  persons.add(p);
  }
  //移除
  public void detach(Person p) {
  persons.remove(p);
  }
  //显示测评情况
  public void display(Action action) {
  for(Person p: persons) {
    p.accept(action);
  }
  }
}

public class Client {
  public static void main(String[] args) {
  // TODO Auto-generated method stub
  //创建ObjectStructure
  ObjectStructure objectStructure = new ObjectStructure();
  objectStructure.attach(new Man());
  objectStructure.attach(new Woman());
  //成功
  Success success = new Success();
  objectStructure.display(success);
  System.out.println("===============");
  Fail fail = new Fail();
  objectStructure.display(fail);
  System.out.println("=======给的是待定的测评========");
  Wait wait = new Wait();
  objectStructure.display(wait);
  }
}