12.8总结

package test25;

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

package test25;

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

package test25;

import java.util.ArrayList;
import java.util.Iterator;

public class BuyBasket{

private ArrayList list = new ArrayList();

public void accept(Visitor visitor){
    Iterator iterator = list.iterator();
    while (iterator.hasNext()){
        ((Product)iterator.next()).accept(visitor);
    }
}

public void addProduce(Product product){
    list.add(product);
}

public void removeProduce(Product product){
    list.remove(product);
}

}

package test25;

public class Client {

public static void main(String[] args) {
    Product b1 = new Book();
    Product b2 = new Book();
    Product a1 = new Apple();
    Visitor visitor;

    BuyBasket basket = new BuyBasket();
    basket.addProduce(b1);
    basket.addProduce(b2);
    basket.addProduce(a1);

    visitor = new Packager();
    visitor.setName("张三");
    basket.accept(visitor);
}

}

package test25;

public class Customer extends Visitor{
@Override
public void visit(Apple apple) {
System.out.println("顾客"+name+"选苹果");
}

@Override
public void visit(Book book) {
    System.out.println("顾客"+name+"买书");
}

}

package test25;

public class Packager extends Visitor{
@Override
public void visit(Apple apple) {
System.out.println("打包员"+name+"打包苹果");
}

@Override
public void visit(Book book) {
    System.out.println("打包员"+name+"打包书籍");
}

}

package test25;

public interface Product {

void accept(Visitor visitor);

}

package test25;

public class Saler extends Visitor{
@Override
public void visit(Apple apple) {
System.out.println("收银员"+
name+"给苹果过称，计算价格");
}

@Override
public void visit(Book book) {
    System.out.println("收银员"+name+"直接计算书的价格");
}

}

package test25;

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);

}