Java访问者设计模式详细讲解

public interface Fruit {
    int price();
    void draw();
    int accept(Visit visit);
}
public class Apple implements Fruit {
    private int price = 100;
    public Apple(){
    }
    public Apple(int price){
        this.price = price;
    }
    public void pack(AppleBag bag){
        bag.pack();
    }
    @Override
    public int price() {
        return price;
    }
    @Override
    public void draw() {
        System.out.print("苹果红富士");
    }
    public void setPrice(int price) {
        this.price = price;
    }
    public int accept(Visit visit){
        /*指针可以传递真实类型*/
        return visit.sell(this);
    }
}
public class Banana implements Fruit {
    private int price = 60;
    @Override
    public int price() {
        return price;
    }
    public void pack(BananaBag bag){
        bag.pack();
    }
    @Override
    public void draw() {
        System.out.print("仙人蕉");
    }
    public int accept(Visit visit){
        return visit.sell(this);
    }
    public void setPrice(int price) {
        this.price = price;
    }
}
public class Orange implements Fruit {
    private String name = "";
    private int price = 70;
    public Orange(String name,int price){
        this.price = price;
        this.name = name;
    }
    public void pack(OrangeBag bag){
        bag.pack();
    }
    @Override
    public int price() {
        return price;
    }
    @Override
    public void draw() {
        System.out.print("砂糖桔");
    }
    public int accept(Visit visit){
        return visit.sell(this);
    }
    public void setPrice(int price) {
        this.price = price;
    }
}
public class Visit {
	/*苹果计价*/
	public int sell(Apple apple){
		System.out.println("apple's price: ￥50");
		return 50;
	}
	/*桔子计价*/
	public int sell(Orange orange){
		System.out.println("orange's price: ￥20");
		return 20;
	}
	/*香蕉计价*/
	public int sell(Banana banana){
		System.out.println("banana's price: ￥30");
		return 30;
	}
	//其它水果计价
	public int sell(Fruit fruit){
		System.out.println("other price: ￥10");
		return 10;
	}
}
public class VisitClient {
    private static Visit visit = new Visit();
    /*库存*/
    private static List<Fruit> list = new ArrayList<>();
    static {
        list.add(StaticFactory.getFruitApple());
        list.add(StaticFactory.getFruitOrange());
        list.add(StaticFactory.getFruitBanana());
        list.add(StaticFactory.getFruitApple());
        list.add(StaticFactory.getFruitOrange());
    }
    private static int price() {
        int total = 0;
        for (Fruit fruit : list) {
            total += fruit.accept(visit);
        }
        System.out.println("总价值：" + total);
        return total;
    }
      public static void main(String[] args) {
        price();
    }