2023/11/3 每日总结

今天完成了设计模式实验25

实验 25：访问者模式

本次实验属于模仿型实验，通过本次实验学生将掌握以下内容：

1、理解访问者模式的动机，掌握该模式的结构；

2、能够利用访问者模式法解决实际问题。

 

[实验任务一]：打包员

在我们课堂上的“购物车”的例子中，增加一个新的访问者：打包员，负责对购物车中货物装包。

 

package org.test25;

public class Apple implements Product{
    @Override
    public void accept(Visitor visitor) {
        visitor.visit(this);
    }
}


package org.test25;

public class Book implements Product {
    @Override
    public void accept(Visitor visitor) {
        visitor.visit(this);
    }
}




package org.test25;

import java.util.ArrayList;
import java.util.List;

public class BuyBasket {
    private List<Product> productList=new ArrayList<>();
    public void accept(Visitor visitor){
        for (Product product:productList){
            product.accept(visitor);
        }
    }
    public void addProduct(Product product){
        productList.add(product);
    }
    public void removeProduct(Product product){
        productList.remove(product);
    }
}





package org.test25;

public class Client {
    public static void main(String[] args) {
        Apple apple = new Apple();
        Book book = new Book();
        BuyBasket buyBasket = new BuyBasket();
        Packager packager = new Packager("张三");
        buyBasket.addProduct(book);
        buyBasket.addProduct(apple);
        buyBasket.accept(packager);
    }
}



package org.test25;

public class Packager extends Visitor{
    public Packager(String name) {
        super(name);
    }

    @Override
    public void visit(Apple apple) {
        System.out.println(this.name+"已经打包苹果");
    }

    @Override
    public void visit(Book book) {
        System.out.println(this.name+"已经打包图书");
    }
}



package org.test25;

public interface Product {
    void accept(Visitor visitor);
}



package org.test25;

public abstract class Visitor {
    protected String name;

    public Visitor(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
    public abstract void visit(Apple apple);
    public abstract void visit(Book book);
}