A brief introduction to proxy mode in C++ design patterns

Proxy mode (Proxy): Provides a proxy for other objects to control access to this object (the agent, that is, the person).

To implement a method in C#, you need to use an interface to define the required methods, while in C++ you need to implement a class as an interface, which defines the required methods. For me, I don't need to participate in the specific activities, but the agent will do it. The client (third party) does not know me either, thus acting as an agent.

The above means: Use a class to encapsulate the required proxy methods.

Application of proxy mode:

Remote creation, that is, providing local representation for an object in different address spaces. This hides the fact that an object exists in a different address space. [DP]

Virtual agents are expensive objects to create as needed. It is used to store real objects that require a long time to instantiate. For example: when opening a large HTML web page, the picture we see can only be seen after downloading, and the unopened picture box is accessed through a virtual proxy. Substitute real picture. At this point the agent stores the path and dimensions of the real image.

Security proxy is used to control the permissions when accessing real objects [DP]. It is generally used when objects should have different access permissions.

Intelligent guidance means that when the real object is called, the agent handles other things [DP].

Take the agency mobile phone package as an example:

Test case:

[code]int main(){//整个过程中，本人都没有出现
    std::string name = "Jarrett";
    //第三方公司
    Company cp(name);  //申请人（本人）的名字告诉公司

    //代理人
    Proxy *px = new Proxy(cp);

    //办理58元套餐
    px->A58();
    //办理88元套餐
    px->A88();
    //办理128元套餐
    px->A128();

    return 0;
}

Proxy class implementation method:

[code]//主体，提供接口。无需实例化，定义为纯虚函数
class Subject{
public:
    virtual void A58()const = 0;
    virtual void A88()const = 0;
    virtual void A128()const = 0;
};

//第三方公司
class Company{   
public:
    std::string name; //公司要知道办理套餐本人的名字
    Company(std::string na):name(na){}  
};

//本人（被代理人）
class oneSelf: public Subject{
private:
    Company cp; //本人要知道自己对谁做什么，此处自己知道要对哪个公司办理套餐
public:
    oneSelf(Company c):cp(c){} //此处由代理类来初始化

    void A58()const override{
        std::cout << cp.name << " for 58 packages.\n"; //告诉移动公司，我要办58套餐
    }

    void A88()const override{
        std::cout << cp.name << " for 88 packages.\n";
    }

    void A128()const override{
        std::cout << cp.name << " for 128 packages.\n";
    }
};

class Proxy:public Subject{
private:
    //代理谁？
    oneSelf os;
public:
    Proxy(Company cp):os(oneSelf(cp)){}  //此处初始化本人的构造函数，达到了代理的目的
    void A58()const override{
        os.A58();
    }

    void A88()const override{
        os.A88();
    }

    void A128()const override{
        os.A128();
    }

};

The above is a brief introduction to C++ design patterns For the content of the proxy mode, please pay attention to the PHP Chinese website (www.php.cn) for more related content!