设计模式之建造者（builder）模式

时间：2010-10-05 来源：chenchao40322

建造者模式把一个复杂的对象的与他的表示分离，使得同样的构造过程可以构建不同的表示（大话设

计模式）。它把对象的各个组件的组装隐藏起来，对外提供一个组装方法，并对外提供一个对象表现

的抽象接口，调用者通过实现此表现抽象接口来实现多种对象的表现，然后调用组装方法来组装出目

标表对象。

代码如下：

//零部件的基类,外部调用者通过实现此接口来表现各个零部件

class PersonBuilder
{
public:
    PersonBuilder(){};
    virtual ~PersonBuilder(){};
    virtual void BuildHead()=0;
    virtual void BuildBody()=0;
    virtual void BuildArmLeft()=0;
    virtual void BuildArmRight()=0;
    virtual void BuildLegLeft()=0;
    virtual void BuildLegRight()=0;
};

//组件组装类，外部通过调用此类的组装方法

CreatePerson来组装出对象。

class PersonDirector
{
private:
    PersonBuilder* _pPersonBuilder;
public:
    PersonDirector():_pPersonBuilder(0){};
    PersonDirector(PersonBuilder* pPersonBuilder):_pPersonBuilder(pPersonBuilder){};
    ~PersonDirector();
    void CreatePerson();
};

PersonDirector::~PersonDirector()
{
if(_pPersonBuilder!=0)
delete _pPersonBuilder;
}

void PersonDirector::CreatePerson()
{
    _pPersonBuilder->BuildHead();
    _pPersonBuilder->BuildBody();
    _pPersonBuilder->BuildArmLeft();
    _pPersonBuilder->BuildArmRight();
    _pPersonBuilder->BuildLegLeft();
    _pPersonBuilder->BuildLegRight();
}

//调用者实现的一个组件的表现

class PersonFatBuilder : public PersonBuilder
{
public:
    PersonFatBuilder(){};
    ~PersonFatBuilder(){};
    void BuildHead();
    void BuildBody();
    void BuildArmLeft();
    void BuildArmRight();
    void BuildLegLeft();
    void BuildLegRight();
};

void PersonFatBuilder::BuildHead()
{
    std::cout<<"胖头"<<std::endl;
}
void PersonFatBuilder::BuildBody()
{
    std::cout<<"胖身子"<<std::endl;
}
void PersonFatBuilder::BuildArmLeft()
{
    std::cout<<"胖左手"<<std::endl;
}
void PersonFatBuilder::BuildArmRight()
{
    std::cout<<"胖右手"<<std::endl;
}
void PersonFatBuilder::BuildLegLeft()
{
    std::cout<<"胖左腿"<<std::endl;
}
void PersonFatBuilder::BuildLegRight()
{
    std::cout<<"胖右腿"<<std::endl;
}

//调用者的调用代码。

int main()
{
    PersonDirector* pPersonDirector=new   PersonDirector(new PersonFatBuilder);
    pPersonDirector->CreatePerson();
    return 0;
}