9 建造者模式

好菜没回味道不同——建造者模式

建造者模式（Builder），又声称其模式，讲一个复杂对象的构建与它的表示分离，使得同样的构建过程可以创建不同的表示。

#include <iostream>

 using std::cout;
 using std::endl;

 //抽象的建造人的类
 class PersonBuilder
{
 public:
    virtual void BuildHead() = 0;
    virtual void BuildBody() = 0;
    virtual void BuildArmLeft() = 0;
    virtual void BuildArmRight() = 0;
    virtual void BuildLegLeft() = 0;
    virtual void BuildLegRight() = 0;

};

 //具体建造者类，建造瘦人
//因为抽象建造类中的建造方法都是纯虚函数
//这就要求具体建造类中必须一个不漏的全部重写
//否则生成具体对象时会编译出错
class PersonThinBuilder : public PersonBuilder
{
public:
    void BuildHead()
    {
        cout<<"绘制瘦人的Head"<<endl;
    }
    void BuildBody()
    {
        cout<<"绘制瘦人的Body"<<endl;
    }
    void BuildArmLeft()
    {
        cout<<"绘制瘦人的ArmLeft"<<endl;
        
    }
    void BuildArmRight()
    {
        cout<<"绘制瘦人的ArmRight"<<endl;    
    }
    void BuildLegLeft()
    {
        cout<<"绘制瘦人的LegLeft"<<endl;    
    }
    void BuildLegRight()
    {
        cout<<"绘制瘦人的LegRight"<<endl;    
    }
};

class PersonFatBuilder : public PersonBuilder
{
public:
    void BuildHead()
    {
        cout<<"绘制胖人的Head"<<endl;
    }
    void BuildBody()
    {
        cout<<"绘制胖人的Body"<<endl;
    }
    void BuildArmLeft()
    {
        cout<<"绘制胖人的ArmLeft"<<endl;
        
    }
    void BuildArmRight()
    {
        cout<<"绘制胖人的ArmRight"<<endl;    
    }
    void BuildLegLeft()
    {
        cout<<"绘制胖人的LegLeft"<<endl;    
    }
    void BuildLegRight()
    {
        cout<<"绘制胖人的LegRight"<<endl;    
    }
};

//指挥者类，用来控制建造过程，也用它来隔离用户与建造过程的关联
//用户不需要意义调用Build*函数，而只需要调用一个Create接口
//避免了用户可能遗漏某些部分函数调用的情况
class PersonDirector
{
public:
    PersonDirector(PersonBuilder* pb)
    {
        this->pb = pb;
    }
    void CreatePerson()
    {
        pb->BuildHead();
        pb->BuildBody();
        pb->BuildArmLeft();
        pb->BuildArmRight();
        pb->BuildLegLeft();
        pb->BuildLegRight();
    }
private:
    PersonBuilder *pb;
    
};

int main()
{
    PersonThinBuilder *ptb = new PersonThinBuilder();
    PersonDirector *pdThin = new PersonDirector(ptb);
    pdThin->CreatePerson();
    
    cout<<endl;

    PersonFatBuilder *pfb = new PersonFatBuilder();
    PersonDirector *pdFat = new PersonDirector(pfb);
    pdFat->CreatePerson();
    return 0;
}

#include <iostream>
#include <string>
#include <list>

using std::cout;
using std::endl;
using std::string;
using std::list;
using std::iterator;

//产品类
class Product
{
public:
    //添加产品部件
    void Add(string part)
    {
        parts.push_back(part);
    }
    void Show()
    {
        cout<<"产品 创建——"<<endl;
        for(list<string>::iterator iter = parts.begin(); iter != parts.end(); ++iter)
        {
            cout<<*iter<<endl;
        }
    }
private:
    list<string> parts;
};

//Builder类——抽象建造者类
class Builder
{
public:
    virtual void BuilderPartA() = 0;
    virtual void BuilderPartB() = 0;
    virtual Product* GetResult() = 0;
};

//ConcreteBuilder1——具体建造者类
class ConcreteBuilder1 : public Builder
{
public:
    ConcreteBuilder1()
    {
        product = new Product();
    }
    void BuilderPartA()
    {
        product->Add("部件A");
    }
    void BuilderPartB()
    {
        product->Add("部件B");
    }
    Product* GetResult()
    {
        return product;
    }
private:
    Product *product;
};

//ConcreteBuilder2——具体建造者类
class ConcreteBuilder2 : public Builder
{
public:
    ConcreteBuilder2()
    {
        product = new Product();
    }
    void BuilderPartA()
    {
        product->Add("部件X");
    }
    void BuilderPartB()
    {
        product->Add("部件Y");
    }
    Product* GetResult()
    {
        return product;
    }
private:
    Product *product;
};

//Director类——指挥者类
class Director
{
public:
    void Construct(Builder *builder)
    {
        builder->BuilderPartA();
        builder->BuilderPartB();
    }
};

int main()
{
    Director *director = new Director();
    
    Builder *b1 = new ConcreteBuilder1();
    director->Construct(b1);//实际的建造过程
    Product *p1 = b1->GetResult();
    p1->Show ();

    cout<<endl;

    Builder *b2 = new ConcreteBuilder2();
    director->Construct(b2);//实际的建造过程
    Product *p2 = b2->GetResult();
    p2->Show ();

    return 0;
}