抽象工厂

2019-11-08 00:44:15

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来源：转载

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工厂模式

客户类和工厂类分开。消费者任何时候需要某种产品，只需向工厂请求即可。消费者无需修改就可以接纳新产品。缺点是当产品修改时，工厂类也要做相应的修改。如：如何创建及如何向客户端提供。

消费者不固定，工厂者不固定（工厂根据消费者动作）

实现消费者抽象类，消费者派生类的实现，实例化就是消费者

操作的抽象类，实现派生类各种操作，实例化的操作

工厂的抽象类，抽象类包含了两个抽象类的接口（消费者，操作）

抽象类实现了工厂类的抽象，实例化的派生类，实现工厂

根据用户设置用户，根据操作设置操作

class IUser{public: virtual void getUser() = 0; //纯虚接口类，抽象类 virtual void setUser() = 0;};class SqlUser :public IUser //继承抽象实现sql数据库使用者的实例化{public: void getUser() { cout << "在sql中返回user" << endl; } void setUser() { cout << "在sql中设置user" << endl; }};class accessUser :public IUser //继承抽象实现access数据库使用者的实例化{public: void getUser() { cout << "在Access中返回user" << endl; } void setUser() { cout << "在Access中设置user" << endl; }};class IDepartment //抽象类，提供接口{public: virtual void getDepartment() = 0; virtual void setDepartment() = 0;};class SqlDepartment :public IDepartment //SQL操作的实现{public: void getDepartment() { cout << "在sql中返回Department" << endl; } void setDepartment() { cout << "在sql中设置Department" << endl; }};class AccessDepartment :public IDepartment //access操作的实现{public: void getDepartment() { cout << "在Access中返回Department" << endl; } void setDepartment() { cout << "在Access中设置Department" << endl; }};class IFactory //抽象工厂{public: virtual IUser *createUser() = 0; virtual IDepartment *createDepartment() = 0;};class SqlFactory :public IFactory //抽象工厂一个实现{public: IUser *createUser() { return new SqlUser(); } IDepartment *createDepartment() { return new SqlDepartment(); }};class AccessFactory :public IFactory // 抽象工厂一个实现{public: IUser *createUser() { return new AccessUser(); } IDepartment *createDepartment() { return new AccessDepartment(); }};/*************************************************************///变相的实现了静态类class DataAccess{PRivate: static string db; //string db="access";public: static IUser *createUser() { if (db == "access") { return new AccessUser(); } else if (db == "sql") { return new SqlUser(); } } static IDepartment *createDepartment() { if (db == "access") { return new AccessDepartment(); } else if (db == "sql") { return new SqlDepartment(); } }};string DataAccess::db = "sql";/*************************************************************/int main12321312321(){ //IFactory *factory=new SqlFactory(); IFactory *factory;//抽象工厂 IUser *user;//抽象消费者 IDepartment *department;//提供的操作 factory = new AccessFactory();//基类的指针指指向派生类的对象 user = factory->createUser();//基类的指针指向派生类的对象 department = factory->createDepartment();//基类的指针指向派生类的对象 user->getUser(); user->setUser();//访问acesss接口 department->getDepartment(); department->setDepartment();//接口 user = DataAccess::createUser(); department = DataAccess::createDepartment(); user->getUser(); user->setUser(); department->getDepartment(); department->setDepartment(); cin.get(); return 0;}