访问者模式

/**
 * 访问者模式:就是不同的人(访问者)对同一种资源(衣服)下的不同分类的表现不一致:举个例子,小孩,男人,女人,去服装店里逛,对童装,男装,女装的感兴趣是不一样的;
 * 这里小孩,男孩,女人就是访问者,男装,女装,童装就是资源或者elment,服装店就是对象结构:
 *
 * 小孩逛商店:对童装感兴趣 男人逛商店:对男装感兴趣,也会给小朋友买衣服,女人对童装,女装,男装都会感兴趣,因为可能会给子女,老公买衣服:
 * 所以访问者模式的结构:
 *
 * 1.一个访问者接口Visistor和多个实现类(如本例子中的男人,女人,小孩),该接口会有访问各种资源的方法,如本例中,每个访问者都会对男装,女装,童装进行访问
 * 2.资源接口Elemnt和多个实现类,如本例的童装,男装,女装,每个资源类都会提供一个接受访问者的接口,在该接口调用访问者访问该资源的方法
 * 3.一个对象结构:如本例的服装店,简单来说就是存储资源集合的对象
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//访问者
public interface Visistor {
    //访问者可以访问所有的资源子类(这里是重点,有多少个子类,就添加多少个访问方法)
    void buyChildrenCloth(ChildrenCloth cloth);
    void buyManCloth(ManCloth cloth);
    void buyWomenCloth(WomenCloth cloth);
    //统计每个访问者买衣服总花费金额
    void cost();

}
//访问者---小孩
public class Children implements Visistor {
    private BigDecimal amount=BigDecimal.ZERO;

    @Override
    public void buyChildrenCloth(ChildrenCloth cloth) {
        System.out.println("我是小朋友,买衣服只会买小朋友的衣服");
        amount=amount.add(cloth.getAmount());
    }

    @Override
    public void buyManCloth(ManCloth cloth) {
        System.out.println("我是小朋友,不会买妈妈的衣服");
    }

    @Override
    public void buyWomenCloth(WomenCloth cloth) {
        System.out.println("我是小朋友,不会买爸爸的衣服");
    }

    @Override
    public void cost() {
        System.out.println("我是小朋友这次买衣服总花费:"+amount.toString());
    }


}
//访问者--男孩
public class Man implements Visistor {
    private BigDecimal amount=BigDecimal.ZERO;
    @Override
    public void buyChildrenCloth(ChildrenCloth cloth) {
        System.out.println("我是爸爸,我会帮小朋友买衣服");
        amount=amount.add(cloth.getAmount());
    }

    @Override
    public void buyManCloth(ManCloth cloth) {

        System.out.println("我是爸爸,我不会买老婆的衣服");

    }

    @Override
    public void buyWomenCloth(WomenCloth cloth) {
        System.out.println("我是爸爸,我会买自己的衣服");
        amount=amount.add(cloth.getAmount());
    }
    @Override
    public void cost() {
        System.out.println("我是爸爸,这次买衣服总花费:"+amount.toString());
    }
}
//访问者--女孩
public class Women implements Visistor {
    private BigDecimal amount=BigDecimal.ZERO;
    @Override
    public void buyChildrenCloth(ChildrenCloth cloth) {
        System.out.println("我是妈妈,我会给小朋友买衣服");
        amount=amount.add(cloth.getAmount());
    }

    @Override
    public void buyManCloth(ManCloth cloth) {
        System.out.println("我是妈妈,我会给老公买衣服");
        amount=amount.add(cloth.getAmount());
    }

    @Override
    public void buyWomenCloth(WomenCloth cloth) {
        System.out.println("我是妈妈,我会给自己买衣服");
        amount=amount.add(cloth.getAmount());
    }
    @Override
    public void cost() {
        System.out.println("我是妈妈,这次买衣服总花费:"+amount.toString());
    }
}
//资源Element
public abstract class Cloth {
    protected BigDecimal amount;
    //资源接受的访问者
    abstract void accept(Visistor visistor);

}
//资源--童装
public class ChildrenCloth extends Cloth{


    public ChildrenCloth(BigDecimal amount) {
        this.amount = amount;
    }

    public BigDecimal getAmount() {
        return amount;
    }

    @Override
    public void accept(Visistor visistor) {
        visistor.buyChildrenCloth(this);
    }
}
//资源--男装
public class ManCloth extends Cloth {


    public ManCloth(BigDecimal amount) {
        this.amount = amount;
    }

    public BigDecimal getAmount() {
        return amount;
    }

    public void setAmount(BigDecimal amount) {
        this.amount = amount;
    }

    @Override
    public void accept(Visistor visistor) {
        visistor.buyManCloth(this);
    }
}
//资源女装
public class WomenCloth extends Cloth {


    public WomenCloth(BigDecimal amount) {
        this.amount = amount;
    }

    public BigDecimal getAmount() {
        return amount;
    }

    public void setAmount(BigDecimal amount) {
        this.amount = amount;
    }

    @Override
    public void accept(Visistor visistor) {
        visistor.buyWomenCloth(this);
    }
}
//结构对象,存储资源
public class ClothShop {
    private List<Cloth> list=new ArrayList<>();

    public void addCloth(Cloth cloth){
        list.add(cloth);
    }
    //不同访问者逛商店
    public void show(Visistor visistor){
        for (Cloth cloth : list) {
            cloth.accept(visistor);
        }
    }
}
public class Test {
    public static void main(String[] args) {

        //创建一个服装店,并进货童装,男装,女装
        ClothShop clothShop = new ClothShop();//服装店
        ChildrenCloth childrenCloth = new ChildrenCloth(new BigDecimal("100"));//童装
        ManCloth manCloth = new ManCloth(new BigDecimal("200"));//男装
        WomenCloth womenCloth = new WomenCloth(new BigDecimal("300"));//女装
        clothShop.addCloth(childrenCloth);//进货童装
        clothShop.addCloth(manCloth);//进货男装
        clothShop.addCloth(womenCloth);//进货女装


        //儿童逛服装店
        Children children = new Children();//儿童
        clothShop.show(children);//逛店
        children.cost();//总花费

        //老公逛服装店
        Man man = new Man(); //老公
        clothShop.show(man);//逛店
        man.cost();//总花费

        //老婆逛服装店
        Women women = new Women(); //老婆
        clothShop.show(women);//逛店
        women.cost();//总花费


    }
}