装饰器模式

在原来的基础上，增加一个功能。

比如有个手机类，你可以写个抽象的装饰器类，该类中加入个手机类的成员，因为后期要用到这个手机类，且无法被更改，则可用protected：成员。

假如要写个手机贴膜的装饰器，则可继承写好的装饰器，然后对相应的虚函数功能进行重写。

代码示例：

#define  _CRT_SECURE_NO_WARNINGS 
#include <iostream>

using namespace std;

//抽象的手机类
class Phone
{
public:
    virtual void show() = 0;
};

class iPhone :public Phone
{
public:
    virtual void show() {
        cout << "秀出了iphone" << endl;
    }
};

class Mi :public Phone
{
    virtual void show() {
        cout << "秀出了小米手机" << endl;
    }
};

//写一个抽象的装饰器
class Decorator :public Phone
{
public:
    Decorator(Phone *phone) {
        this->phone = phone;
    }

    virtual void show() = 0;
protected:
    Phone * phone; //拥有一个 所有手机的父类指针
};

//具体的手机贴膜装饰器
class MoDecorator :public Decorator
{
public:
    MoDecorator(Phone *phone) : Decorator(phone) {}
    virtual void show() {
        this->phone->show();  //保持原有的show

        this->mo(); //额外添加一个 mo的方法
    }

    //膜装饰器，可以修饰添加的方法
    void mo() {
        cout << "手机有了贴膜" << endl;
    }
};

//皮套的装饰器类
class TaoDecorator :public Decorator
{
public:
    TaoDecorator(Phone *phone) : Decorator(phone) {}
    virtual void show() {
        this->phone->show();
        tao();
    }

    void tao() {
        cout << "手机有了皮套" << endl;
    }
};



int main(void)
{
    Phone *phone = new iPhone;
    phone->show();
    cout << " -----  " << endl;
    Phone * moPhone = new MoDecorator(phone);
    moPhone->show();
    cout << " -----  " << endl;
    Phone * taoPhone = new TaoDecorator(phone);
    taoPhone->show(); 

    cout << " ------  " << endl;
    Phone *moTaoPhone = new TaoDecorator(moPhone);
    moTaoPhone->show(); //moPhone.show() + tao() ==  phone.show() + mo() + tao();

    
    return 0;
}

 

举个英雄联盟的例子：

代码：

#define  _CRT_SECURE_NO_WARNINGS 
#include <iostream>

using namespace std;

class Hero
{
public:
    virtual void status() = 0;
};

class Akali :public Hero
{
public:
    virtual void status()  {
        cout << "HP: 1000" << endl;
        cout << "AP: 500" << endl;
        cout << "AD: 50" << endl;
    }
};

//英雄的装饰器
class Decorator :public Hero
{
public:
    Decorator(Hero *hero){
        this->hero = hero;
    }
    virtual void status() = 0;

protected:
    Hero *hero;
};

//日炎斗篷的装饰器
class RYDecorator :public Decorator
{
public:
    RYDecorator(Hero *hero) : Decorator(hero) {}
    virtual void status()  {
        this->hero->status(); //先调用被装饰的 英雄的基本状态

        cout << "HP + 100000" << endl;
    }

};

//深渊权杖的装备装饰器
class SYQZDecorator :public Decorator
{
public:
    SYQZDecorator(Hero *hero) : Decorator(hero) {}
    virtual void status() {
        this->hero->status();

        cout << "AP +50000 " << endl;
    }
};

int main(void)
{
    Hero *akali = new Akali;
    cout << "akali的初始状态" << endl;
    akali->status();

    cout << "通过日然斗篷创建新的akali" << endl;
    Hero *ryAkali = new RYDecorator(akali);
    ryAkali->status();

    cout << "再通过 深渊权杖的装备装饰器 修饰日炎akali" << endl;
    Hero *syAkali = new SYQZDecorator(ryAkali);
    syAkali->status();
    
    return 0;
}