软件设计 石家庄铁道大学信息学院
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。
实验要求：
1. 画出对应的类图；
2. 提交源代码；
3. 注意编程规范。
- Apple.java
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package org.example;
/** * @author IronBro * @version 1.0 * @description: TODO * @date 2024/11/27 */ public class Apple implements Product{ @Override public void accept(Visitor visitor) { visitor.visit(this); } }
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- Book.java
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package org.example;
/** * @author IronBro * @version 1.0 * @description: TODO * @date 2024/11/27 */ public class Book implements Product{ @Override public void accept(Visitor visitor) { visitor.visit(this); } }
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- BuyBasket.java
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package org.example;
/** * @author IronBro * @version 1.0 * @description: TODO * @date 2024/11/27 */
import java.util.ArrayList; import java.util.Iterator;
public class BuyBasket { private ArrayList list = new ArrayList();
public void accept(Visitor visitor) { Iterator i = list.iterator(); while (i.hasNext()) { ((Product) i.next()).accept(visitor); } }
public void addProduct(Product p) { list.add(p); }
public void removeProduct(Product p) { list.remove(p); } }
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- Customer.java
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package org.example;
import org.example.Book;
/** * @author IronBro * @version 1.0 * @description: TODO * @date 2024/11/27 */ public class Customer extends Visitor{ @Override public void visit(Apple apple) { System.out.println("顾客"+name+"付钱买苹果"); }
@Override public void visit(Book book) { System.out.println("顾客"+name+"付钱买书"); } }
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- Packer.java
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package org.example;
import org.example.Book;
/** * @author IronBro * @version 1.0 * @description: TODO * @date 2024/11/27 */ public class Packer extends Visitor{ @Override public void visit(Apple apple) { System.out.println("装包员"+name+"打包苹果"); }
@Override public void visit(Book book) { System.out.println("装包员"+name+"打包书"); } }
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- Product.java
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package org.example;
/** * @author IronBro * @version 1.0 * @description: TODO * @date 2024/11/27 */ public interface Product { void accept(Visitor visitor); }
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- Saler.java
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package org.example;
import org.example.Book;
/** * @author IronBro * @version 1.0 * @description: TODO * @date 2024/11/27 */ public class Saler extends Visitor { @Override public void visit(Apple apple) { System.out.println("收银员" + name + "计算苹果的价格"); }
@Override public void visit(Book book) { System.out.println("收银员" + name + "计算书的价格"); } }
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- Visitor.java
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package org.example;
import org.example.Book;
/** * @author IronBro * @version 1.0 * @description: TODO * @date 2024/11/27 */ public abstract class Visitor { protected String name;
public void setName(String name) { this.name = name; }
public abstract void visit(Apple apple);
public abstract void visit(Book book); } |
- Client.java
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package org.example;
/** * @author IronBro * @version 1.0 * @description: TODO * @date 2024/11/27 */ public class Client { public static void main(String[] args) { Product p1, p2; Visitor v1, v2, v3; p1 = new Apple(); p2 = new Book(); v1 = new Saler(); v1.setName("小郭"); v2 = new Customer(); v2.setName("小王"); v3 = new Packer(); v3.setName("小张"); BuyBasket basket = new BuyBasket(); basket.addProduct(p1); basket.addProduct(p2); basket.accept(v1); basket.accept(v2); basket.accept(v3); } }
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