006 --- 第9章 原型模式

简述：

　　原型模式用原型实例指定创建对象的种类，并且通过考北这些原型创建新的对象。

　　原型模式包括：抽象原型类、具体原型类。

　　　　抽象原型类：声明一个克隆自身的接扣。

　　　　具体原型类：继承自抽象原型类，实现一个克隆自身的操作。

 应用场景：一般在初始化的信息不发生变化的情况下，克隆是最好的办法，既隐藏了创建对象的细节，又对性能是大大的提高

 

注：开发环境调整为VS2017，操作系统win11

原型模式代码：

#include <iostream>
#include <string>
using namespace std;

// 原型模式
// 抽象原型类
class CPrototype
{
private:
    string m_szID;

public:
    CPrototype() {}

    CPrototype(string szID)
    {
        m_szID = szID;
    }

    void SetID(string szID)
    {
        m_szID = szID;
    }

    string GetID()
    {
        return m_szID;
    }

    virtual CPrototype& Clone() = 0;
};

// 具体原型类
class CConcretePrototype : public CPrototype
{
public:
    CConcretePrototype() {}

    CConcretePrototype(string szID) : CPrototype(szID) {}

    virtual CPrototype& Clone() 
    {
        return (CPrototype&)*this;
    }
};

int main()
{
    CConcretePrototype ConcretePrototype1("GHL");
    CConcretePrototype ConcretePrototype2 = (CConcretePrototype&)ConcretePrototype1.Clone();
    ConcretePrototype2.SetID("GGG");
    cout << ConcretePrototype1.GetID() << endl;
    cout << ConcretePrototype2.GetID() << endl;

    system("pause");
    return 0;
}

输出结果：

 

例：简历的克隆

注：本例在clone()函数中需要用到深拷贝，C#中可以继承ICloneable接口进行实现，但C++需要自己实现。

#include <iostream>
#include <string>
using namespace std;

// 工作经历
class CWorkExperience
{
private:
    string m_szWorkDate;
    string m_szCompany;

public:
    void SetWorkDate(string szWorkDate)
    {
        m_szWorkDate = szWorkDate;
    }
    string GetWorkDate()
    {
        return m_szWorkDate;
    }

    void SetCompany(string szCompany)
    {
        m_szCompany = szCompany;
    }
    string GetCompany()
    {
        return m_szCompany;
    }

    CWorkExperience* Clone()
    {
        CWorkExperience* pWorkExperience = new CWorkExperience();
        pWorkExperience->SetWorkDate(GetWorkDate());
        pWorkExperience->SetCompany(GetCompany());
        return pWorkExperience;
    }
};

// 简历(具体原型类)
class CResume
{
private:
    string m_szName;
    string m_szSex;
    string m_szAge;
    CWorkExperience* m_pWorkExperience;
    
    CResume(CWorkExperience* pWorkExperience) : m_pWorkExperience(NULL)
    {
        m_pWorkExperience = pWorkExperience->Clone();
    }

public:
    CResume() : m_pWorkExperience(NULL) {}

    CResume(string szName) : m_pWorkExperience(NULL)
    {
        m_szName = szName;
        m_pWorkExperience = new CWorkExperience();
    }

    ~CResume()
    {
        if (m_pWorkExperience)
        {
            delete m_pWorkExperience;
            m_pWorkExperience = NULL;
        }
    }

    void SetPersionalInfo(string szSex, string szAge)
    {
        m_szSex = szSex;
        m_szAge = szAge;
    }

    void SetWorkExperience(string szWorkDate, string szCompany)
    {
        m_pWorkExperience->SetWorkDate(szWorkDate);
        m_pWorkExperience->SetCompany(szCompany);
    }

    void Display()
    {
        cout << m_szName << " " << m_szSex << " " << m_szAge << endl;
        cout << "工作经历: " << m_pWorkExperience->GetWorkDate() << " " 
            << m_pWorkExperience->GetCompany() << endl << endl;
    }

    CResume* Clone()
    {
        CResume* pResume = new CResume(m_pWorkExperience->Clone());
        pResume->m_szName = m_szName;
        pResume->m_szSex = m_szSex;
        pResume->m_szAge = m_szAge;
        return pResume;
    }
};

int main()
{
    CResume* pResume1 = new CResume("GHL");
    pResume1->SetPersionalInfo("男", "29");
    pResume1->SetWorkExperience("2018-2020", "MMM");

    CResume* pResume2 = pResume1->Clone();
    pResume2->SetWorkExperience("2016-2018", "BBB");

    pResume1->Display();
    pResume2->Display();

    if (pResume1)
    {
        delete pResume1;
        pResume1 = NULL;
    }
    if (pResume2)
    {
        delete pResume2;
        pResume2 = NULL;
    }

    system("pause");
    return 0;
}

 输出结果：