1、有一个工厂，专门生产不同品牌的汽车。当有人需要从此工厂提货的时候，只需要告诉他，要什么品牌的，就可以了，并不关心这些车是怎么生产出来的。
2、以上方式，如果增加品牌的时候，也要修改工厂，有点麻烦。于是，把工厂也抽象了。
1的类图与实现：
首先，是通用的车
1 /// 2 /// @file Car.h 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:10:31 5 /// 6 7 #ifndef __CAR_H__ 8 #define __CAR_H__ 9 10 #include11 12 namespace marrs{13 14 using std::cout;15 using std::cerr;16 using std::endl;17 18 class Car19 {20 public:21 Car() : b_IsRunning(0){}22 virtual ~Car(){};23 public:24 virtual void Run() = 0;25 virtual void Stop() = 0;26 protected:27 bool b_IsRunning;28 };29 30 }31 32 #endif //__CAR_H__
然后是不同品牌的车，继承自Car
1 /// 2 /// @file Benz.h 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:20:54 5 /// 6 7 #ifndef __BENZ_H__ 8 #define __BENZ_H__ 9 10 #include "Car.h"11 12 namespace marrs{13 14 class Benz15 : public Car16 {17 public:18 ~Benz(){}19 public:20 void Run();21 void Stop();22 };23 24 }25 26 #endif //__BENZ_H__ 1 /// 2 /// @file Benz.cc 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:21:54 5 /// 6 7 #include "Benz.h" 8 9 namespace marrs{10 11 void Benz::Run()12 {13 if (b_IsRunning)14 {15 cerr << "Benz is running!" << endl;16 }17 18 cout << "Benz is going to running!" << endl;19 b_IsRunning = true;20 }21 22 void Benz::Stop()23 {24 if (!b_IsRunning)25 {26 cerr << "Benz isn't running..." << endl;27 }28 29 cout << "Benz is going to stopping!" << endl;30 b_IsRunning = false;31 }32 33 }
1 /// 2 /// @file Audi.h 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:20:54 5 /// 6 7 #ifndef __AUDI_H__ 8 #define __AUDI_H__ 9 10 #include "Car.h"11 12 namespace marrs{13 14 class Audi15 : public Car16 {17 public:18 ~Audi(){}19 public:20 void Run();21 void Stop();22 };23 24 }25 26 #endif//__AUDI_H__ 1 /// 2 /// @file Audi.cc 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:21:54 5 /// 6 7 #include "Audi.h" 8 9 namespace marrs{10 11 void Audi::Run()12 {13 if (b_IsRunning)14 {15 cerr << "Audi is running!" << endl;16 }17 18 cout << "Audi is going to running!" << endl;19 b_IsRunning = true;20 }21 22 void Audi::Stop()23 {24 if (!b_IsRunning)25 {26 cerr << "Audi isn't running..." << endl;27 }28 29 cout << "Audi is going to stopping!" << endl;30 b_IsRunning = false;31 }32 33 }
1 /// 2 /// @file Lamborghini.h 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:20:54 5 /// 6 7 #ifndef __LAMBORGHINI_H__ 8 #define __LAMBORGHINI_H__ 9 10 #include "Car.h"11 12 namespace marrs{13 14 class Lamborghini15 : public Car16 {17 public:18 ~Lamborghini(){}19 public:20 void Run();21 void Stop();22 };23 24 }25 26 #endif//__LAMBORGHINI_H__ 1 /// 2 /// @file Lamborghini.cc 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:21:54 5 /// 6 7 #include "Lamborghini.h" 8 9 namespace marrs{10 11 void Lamborghini::Run()12 {13 if (b_IsRunning)14 {15 cerr << "Lamborghini is running!" << endl;16 }17 18 cout << "Lamborghini is going to running!" << endl;19 b_IsRunning = true;20 }21 22 void Lamborghini::Stop()23 {24 if (!b_IsRunning)25 {26 cerr << "Lamborghini isn't running..." << endl;27 }28 29 cout << "Lamborghini is going to stopping!" << endl;30 b_IsRunning = false;31 }32 33 }
接着，有个生产工厂
1 /// 2 /// @file Factory.h 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:27:42 5 /// 6 7 #ifndef __FACTORY_H__ 8 #define __FACTORY_H__ 9 10 11 #include "Benz.h"12 #include "Audi.h"13 #include "Lamborghini.h"14 15 16 enum Brand17 {18 EN_BRAND_CAR_BANZ = 0,19 EN_BRAND_CAR_AUDI,20 EN_BRAND_CAR_LAMBORGHINI,21 };22 23 24 namespace marrs{25 26 using std::cout;27 using std::endl;28 29 class Factory30 {31 public:32 Car * Produce(int int_brand);33 void Reclaim(Car * car_brand);34 };35 36 }37 38 39 #endif //__FACTORY_H__ 1 /// 2 /// @file Factory.cc 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:39:05 5 /// 6 7 #include "Factory.h" 8 9 namespace marrs{10 11 Car * Factory::Produce(int int_brand)12 {13 switch(int_brand)14 {15 case EN_BRAND_CAR_BANZ:16 return new Benz;17 case EN_BRAND_CAR_AUDI:18 return new Audi;19 case EN_BRAND_CAR_LAMBORGHINI:20 return new Lamborghini; 21 default:break;22 }23 return NULL;24 }25 26 void Factory::Reclaim(Car * car_brand)27 {28 delete car_brand;29 }30 31 } 为了方便统一处理方式，我把车的销毁也放到工厂类里了。
1 /// 2 /// @file main.cc 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:40:59 5 /// 6 7 #include "Factory.h" 8 9 using namespace marrs;10 11 int main()12 {13 Factory factory;14 15 Car * car_first = factory.Produce(EN_BRAND_CAR_BANZ); 16 car_first->Run();17 car_first->Stop();18 factory.Reclaim(car_first);19 20 Car * car_second = factory.Produce(EN_BRAND_CAR_AUDI); 21 car_second->Run();22 car_second->Stop();23 factory.Reclaim(car_second);24 25 Car * car_third = factory.Produce(EN_BRAND_CAR_LAMBORGHINI); 26 car_third->Run();27 car_third->Stop();28 factory.Reclaim(car_third);29 30 }
编译，运行
[ccx@ubuntu ~/object-oriented/Factory-Pattern]$>g++ * -o car_factory.exe[ccx@ubuntu ~/object-oriented/Factory-Pattern]$>./car_factory.exe Benz is going to running!Benz is going to stopping!Audi is going to running!Audi is going to stopping!Lamborghini is going to running!Lamborghini is going to stopping!
2的类图与实现 （画图功底不行....略乱）
在1的基础之上，修改Factory
1 /// 2 /// @file Factory.h 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:27:42 5 /// 6 7 #ifndef __FACTORY_H__ 8 #define __FACTORY_H__ 9 10 11 #include "Car.h"12 13 namespace marrs{14 15 using std::cout;16 using std::endl;17 18 class Factory19 {20 public:21 virtual ~Factory(){}22 public:23 virtual Car * Produce() = 0;24 void Reclaim(Car * car_brand)25 {26 delete car_brand;27 }28 };29 30 }31 32 33 #endif //__FACTORY_H__
然后是不同的工厂
1 /// 2 /// @file Benz_Factory.h 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 21:21:58 5 /// 6 7 #ifndef __BENZ_FACTORY_H__ 8 #define __BENZ_FACTORY_H__ 9 10 #include "Factory.h"11 #include "Benz.h"12 13 namespace marrs{14 15 class BenzFactory16 : public Factory17 {18 public:19 Car * Produce()20 {21 return new Benz;22 }23 };24 25 }26 27 #endif // __BENZ_FACTORY_H__ 1 /// 2 /// @file Audi_Factory.h 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 21:21:58 5 /// 6 7 #ifndef __AUDI_FACTORY_H__ 8 #define __AUDI_FACTORY_H__ 9 10 #include "Factory.h"11 #include "Audi.h"12 13 namespace marrs{14 15 class AudiFactory16 : public Factory17 {18 public:19 Car * Produce()20 {21 return new Audi;22 }23 };24 25 }26 27 #endif // __AUDI_FACTORY_H__ 1 /// 2 /// @file Lamborghini_Factory.h 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 21:21:58 5 /// 6 7 #ifndef __LAMBORGHINI_FACTORY_H__ 8 #define __LAMBORGHINI_FACTORY_H__ 9 10 #include "Factory.h"11 #include "Lamborghini.h"12 13 namespace marrs{14 15 class LamborghiniFactory16 : public Factory17 {18 public:19 Car * Produce()20 {21 return new Lamborghini;22 }23 };24 25 }26 27 #endif // __LAMBORGHINI_FACTORY_H__
最后修改main.cc
1 /// 2 /// @file main.cc 3 /// @author marrs(chenchengxi993@gmail.com) 4 /// @date 2017-08-12 20:40:59 5 /// 6 7 #include "Benz_Factory.h" 8 #include "Audi_Factory.h" 9 #include "Lamborghini_Factory.h"10 11 using namespace marrs;12 13 void BenzAction()14 {15 Factory * factory = new BenzFactory;16 Car * car_first = factory->Produce(); 17 car_first->Run();18 car_first->Stop();19 factory->Reclaim(car_first);20 delete factory;21 }22 23 void AudiAction()24 {25 Factory * factory = new AudiFactory;26 Car * car_first = factory->Produce(); 27 car_first->Run();28 car_first->Stop();29 factory->Reclaim(car_first);30 delete factory;31 }32 33 void LamborghiniAction()34 {35 Factory * factory = new LamborghiniFactory;36 Car * car_first = factory->Produce(); 37 car_first->Run();38 car_first->Stop();39 factory->Reclaim(car_first);40 delete factory;41 }42 43 44 int main()45 {46 BenzAction();47 AudiAction();48 LamborghiniAction();49 50 return 0;51 }
编译，运行
[ccx@ubuntu ~/object-oriented/Factory-Pattern_2]$>g++ * -o car_Factory.exe[ccx@ubuntu ~/object-oriented/Factory-Pattern_2]$>./car_Factory.exe Benz is going to running!Benz is going to stopping!Audi is going to running!Audi is going to stopping!Lamborghini is going to running!Lamborghini is going to stopping!