builder pattern--建造者模式 - c++编程基础

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builder pattern--建造者模式

2013-01-01 14:40:28 来源: 作者: 【大中小】浏览:256次

buildre pattern称建造者模式

Builder设计模式，提供一种封装机制来隔离出构成复杂对象的各个子对象的变化，从而保持系统中的相对稳定的将这些子对象组合在一起的算法不随着需求的改变而改变。

Separate the construction of a complex object from its representation so that the same construction process can create different representations. - GoF

建造者（Builder）：

给出一个抽象接口，以规范产品对象的各个组成成分的建造。一般而言，此接口独立于应用程序的商业逻辑。模式中直接创建产品对象的是具体建造者（ConcreteBuilder）角色。具体建造者类必须实现这个接口所要求的方法：一个是建造方法，另一个是结果返还方法。

具体建造者（Concrete Builder）：

担任这个角色的是于应用程序紧密相关的类，它们在应用程序调用下创建产品实例。这个角色主要完成的任务包括：

- 实现Builder角色提供的接口，一步一步完成创建产品实例的过程。

- 在建造过程完成后，提供产品的实例。

指导者（Director）：

担任这个角色的类调用具体建造者角色以创建产品对象。导演者并没有产品类的具体知识，真正拥有产品类的具体知识的是具体建造者对象。

产品（Product）：

产品便是需要建造的复杂对象。

实例：

例如所有的汽车的构建其实是有轮子(Michelin--米其林,Bridgestone--普利司通)、发动机(China,America)、外壳(Normal,Special)三大部分组成。

  1//------------------------三个组成该汽车的基类-----------------------------  2//abstract part  3//其实属性可以有很多，这里就不一一列出来。  4class wheel  5{  6public:  7         wheel(std::string n,int l)  8        :name(n),loadCapacity(l)  9        {} 10virtual std::string getName( )=0; 11virtualint getLG( )=0; 12        ... 13protected: 14         std::string name; 15int loadCapacity;         //负载能力 16        ... 17}; 18 19class engine 20{ 21public: 22         engine(std::string n,int s) 23        :name(n),speed(s) 24        {} 25virtual std::string getName( )=0; 26virtualint getSpeed( )=0; 27        ... 28protected: 29         std::string name; 30int speed ;                   //转速 31        ... 32}; 33 34class shell 35{ 36public: 37         shell(std::string n,std::string c) 38        :name(n),color(c) 39        {} 40virtual std::string getName( )=0; 41virtual std::string getColor( )=0; 42        ... 43protected: 44         std::string name; 45         std::string color        //颜色 46        ... 47}; 48 49//------------------------继承上面基类wheel 的轮胎类----------------------------- 50//concerte part   51//米其林轮胎 52class wheelMichelin:public wheel 53{ 54public: 55         wheelMichelin(std::string n,int l) 56        :wheel(n,l) 57        {} 58        std::string getName( ); 59int getLG( ); 60}; 61 std::string wheelMichelin::getName( ) 62{ 63return name; 64} 65int wheelMichelin::getLG( ) 66{ 67return loadCapacity; 68} 69 70//普利司通轮胎 71class wheelBridgestone:public wheel 72{ 73public: 74         wheelBridgestone(std::string n,int l) 75        :wheel(n,l) 76        {} 77        std::string getName( ); 78int getLG( ); 79}; 80 std::string wheelBridgestone::getName( ) 81{ 82return name; 83} 84int wheelBridgestone::getLG( ) 85{ 86return loadCapacity; 87} 88//--------------------------继承上面基类engine的引擎类----------------------------------------- 89//中国制造 90class engineChina:public engine 91{ 92public: 93         engineChina(std::string n,int s) 94        :engine(n,s) 95        {} 96         std::string getName( ); 97int getSpeed( ); 98}; 99 std::string engineChina::getName( )100{101return name;102}103int engineChina::getSpeed( )104{105return speed;106}107108//美国制造109class engineAmerica:public engine110{111public:112         engineAmerica(std::string n,int s)113        :engine(n,s)114        {}115         std::string getName( );116int getSpeed( );117};118 std::string engineAmerica::getName( )119{120return name;121}122int engineAmerica::getSpeed( )123{124return speed;125}126//----------------------------继承基类shell的外壳类--------------------------------------127//普通128class shellNormal:public shell129{130public:131         shellNormal(std::string n,std::string c)132        :shell(n,c)133        {}134         std::string getName( );135int getColor( );136};137 std::string shellNormal::getName( )138{139return name;140}141 std::string shellNormal::getColor( )142{143return color;144}145146class shellSpecial:public shell147{148public:149         shellSpecial(std::string n,std::string c)150        :name(n),color(c):shell(n,c)151        {}152         std::string getName( );153int getColor( );154};155 std::string shellSpecial::getName( )156{157return name;158}159 std::string shellSpecial::getColor( )160{161return color;162}163//---------------------------产品的基类即车-------------------------------164//abstract product165//车由wheel,engine,shell组成166class car167{168public:169virtualvoid setwh(std::auto_ptr<wheel> w)=0;170virtualvoid seten(std::auto_ptr<engine> e)=0;171         virutal void setsh(std::auto_ptr<shell> s)=0;172virtual std::auto_ptr<wheel> getwh( )=0;173virtual std::auto_ptr<engine> geten( )=0;174virtual std::auto_ptr<shell> getsh( )=0;175protected:176          std::auto_ptr<wheel>    pw;     //轮子177          std::auto_ptr<engine>  pe;     //发动机178          std::auto_ptr<shell>      ps;     //外壳    179};180//------------------------------继承上面基类的车类---------------------------181//concerte product182class AudiCar:public car183{184public:     185void setwh(std::auto_ptr<wheel> w);186void seten(std::auto_ptr<engine> e);187void setsh(std::auto_ptr<shell> s);188             std::auto_ptr<wheel> getwh( );189             std::auto_ptr<engine> geten( );190             std::auto_ptr<shell> getsh( );191};192void AudiCar::setwh(std::auto_ptr<wheel> w)193{194     pw=w;195}196void AudiCar::seten(std::auto_ptr<engine> e)197{198     pe=e;199}200void AudiCar::setps(std::auto_ptr<shell> s)201{202     ps=s;203}204 wheel*  AudiCar::getwh( )205{206if(!pw.get( ))207    {208throw std::invalid_argument("Error: pointer is null!!");209    }210return wh.get( );211}212 engine*  AudiCar::geten( )213{214if(!pe.get( ))215    {216throw std::invalid_argument("Error: pointer is null!!");217    }218return pe.get( );219}220 shell* AudiCar::getsh( )221{222if(!ps.get( ))223    {224throw std::invalid_argument("Error:pointer is null!!");225    }226return ps.get( );227}228229//奔驰230class BenzCar:public car231{232public:233void setwh(std::auto_ptr<wheel> w);234void seten(std::auto_ptr<engine> e);235void setsh(std::auto_ptr<shell> s);236             std::auto_ptr<wheel> getwh( );237             std::auto_ptr<engine> geten( );238             std::auto_ptr<shell> getsh( );239};240 BenzCar::setwh(std::auto_ptr<wheel> w)241{242     pw=w;243}244 BenzCar::seten(std::auto_ptr<engine> e)245{246     pe=e;247}248 BenzCar::setsh(std::auto_ptr<shell> s)249{250     ps=s;251}252 wheel*  BenzCar::getwh( )253{254if(!pw.get( ))255    {256throw std::invalid_argument("Error: pointer is null!!");257    }258return pw.get( );259}260 engine*  BenzCar::geten( )261{262if(!pe.get( ))263    {264throw std::invalid_argument("Error: pointer is null!!");265    }266return pe.get( );267}268 shell*  BenzCar::getsh( )269{270if(!ps.get( ))271    {272throw std::invalid_argument("Error:pointer is null!!");273    }274return  ps.get( );275}276 ------------------------------------------------------------------277class builder278{279public:280virtualvoid buildWheel( )=0;281virtualvoid buildEngine( )=0;282virtualvoid buildShell( )=0;283virtual car*  getCar( )=0;284};285286class BenzBuilder:public builder287{288public:289        BenzBuilder()290         :c(new BenzCar())291        {}292void buildWheel();293void buildEngine();294void buildShell();295         car* getCar( );296private:297         std::auto_ptr<car> c;298};299300//生产奔驰的轮胎301void BenzBuilder::buildWheel( )302{303//采用米其林轮胎304     std::auto_ptr<wheel> w(new wheelMichelin("Michelin",270 ));305     c->setwh(); 306}307308//生产奔驰的引擎309void BenzBuilder::buildEngine( )310{311//美国产引擎312     std::auto_ptr<engine> w(new engineAmercia("Amercia",300));313     c->seten();314}315316//生产奔驰的外壳317void BenzBuilder::buildShell( )318{319     std::auto_ptr<sheel> w(new shellNormol("Normal","Red"));320     c->setsh();321}322323 std::auto_ptr<car> BenzBuilder::getCar( )324{325return c.get( );326}327328class AudiBuilder:public builder329{330public:331        AudiBuilder( )332         :c(new AudiCar( ))333        {}334void buildWheel( );335void buildEngine( );336void buildShell( );337         std::auto_ptr<car> getCar( );338private:339         std::auto_ptr<car> c;340};341342void AudiBuilder::buildWheel( )343{344//采用高通345     std::auto_ptr<wheel> w(new wheelBridgestone("Bridgestone",250));346     c->setwh( );347}348349void AudiBuilder::buildEngine( )350{351//中国产引擎352     std::auto_ptr<engine> w(new EngineChina("China",320));353     c->seten( );354}355356void AudiBuilder::buildShell( )357{358     std::auto_ptr<shell> w(new ShellSpecial("Special","white"));359     c-setsh(w);360}361362 car* AudiBuilder::getCar( )363{364return c.get( );365}366//------------------------------组装汽车--------------------------------------------367class director368{369public:370static std::auto_ptr<car> construct(std::auto_ptr<builder> b);371}372 std::auto_ptr<car> director::construct( std::auto_ptr<builder> b)373{374     b->buildWheel( );375     b->buildEngine( );376     b->buildShell( );377return b->getCar( );378}379380int main(int argc,char **argv)381{382     std::auto_ptr<builder> b(new BenzBuilder( );383     std::auto_ptr<car> c=director::construct(b);384     std::cout<<"The BenzCar's wheel is "<<c->getwh( )->getName( )<<std::endl;385     std::cout<<"Its  loadCapacity  is  "<<c->getwh( )->getLG( )<<std::endl;386     std::cout<<"The BenzCar's engine is made in "<<c->geten()->getName( )<<std::endl; 387     std::cout<<"Its speed is "<<c->geten()->getSpeed()<<std::endl;388     std::cout<<"The BenzCar's shell is "<<c->getsh()->getName( )<<std::endl;389     std::cout<<"Its color is "<<c->getsh()->getColor()<<std::endl;390     std::auto_ptr<builder> b2(new AudiBuilder( );391     std::auto_ptr<car> c2=director::construct(b2);392     std::cout<<"The AudiCar's wheel is "<<c2->getwh( )->getName( )<<std::endl;393     std::cout<<"Its  loadCapacity  is  "<<c2->getwh( )->getLG( )<<std::endl;394     std::cout<<"The AudiCar's engine is made in "<<c2->geten()->getName( )<<std::endl; 395     std::cout<<"Its speed is "<<c2->geten()->getSpeed()<<std::endl;396     std::cout<<"The AudiCar's shell is "<<c2->getsh()->getName( )<<std::endl;397     std::cout<<"Its color is "<<c2->getsh()->getColor()<<std::endl;398return0;399 }

结果


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