设计模式之Builder模式

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设计模式之Builder模式

1.介绍

Builder模式:当我们要创建的对象很复杂的时候,我们要将复杂对象的创建过程和这个对象的表示分离开来,这样做的好处就是通过一步步的进行复杂对象的构建，由于在每一步构造过程中可以引入参数，使得经过相同步骤创建最后得到的对象展示不一样.

2.实例代码

//Product.hclass Product{public:Product();~Product();void ProducePart();protected:private:};class ProdectPart{public:ProductPart();~ProductPart();ProdectPart* BuildPart();protected:private:};//Product.cpp#include "Component.h"Component::Component(){}Component::~Component(){}void Component::Add(const Component&com){}Component* Component::GetChild(int index){return 0;}void Component::Remove(const Component& com){}//Builder.h#include <string>using namespace std;class Product;class Builder{public:virtual ~Builder();virtual void BuildPartA(const string& buildPara)=0;virtual void BuildPartB(const string& buildPara)=0;virtual void BuildPartC(const string& buildPara)=0;protected:Builder();private:};class ConcreteBuilder:public Builder{public:ConcreteBuilder();～ConcreteBuilder();void BuildPartA(const string& buildPara);void BuildPartB(const string& buildPara);Product* GetProduct();protected:private:};//Builder.cpp#include “Builder.h”#include “Product.h”#include <iostream>using namespace std;Builder::Builder(){}Builder::～Builder(){}ConcreteBuilder::ConcreteBuilder(){}ConcreteBuilder::～ConcreteBuilder(){}void ConcreteBuilder::BuilderPatA(const string& buildPara){cout<<“Step1:Build PartA..”<<buildPara<<endl;}void ConcreteBuilder::BuilderPartB(const string& buildPara){cout<<“Step1:Build PartB...”<<buildPara<<endl;}void ConcreteBuilder::BuildPartC(const string& buildPara){cout<<“Step1:Build PartC...”<<buildPara<<endl;}Product* ConcreteBuilder::GetProduct(){BuildPartA(“pre-defined”);BuildPartB(“pre-defined”);BuildPartC(“pre-defined”);return new Product();}//Director.hclass Builder;class Director{public:Director(Builder* bld);～Director();void Construct();protectd:private:Builder* _bld;};//Director.cpp#include “director.h”#include “Builder.h”Director::Director(Builder* bld){_bld = bld;}Director::～Director(){}void Director::Construct(){_bld->BuildPartA(“user-defined”);_bld->BuildPartB(“user-defined”);_bld->BuildPartC(“user-defined”);}//main.cpp#include “Builder.h”#include “Product.h”#include “Director.h”#include <iostream>using namespace std;int main(int agrc,char* argv[]){Director* d=new Director(new ConcreteBuilder());d->Construct();return 0;}

3.结果
Builder模式代码中，BuildPart的参数是通过客户程序员引入的，用“user-deinded”代替，实际是在Construct方法中传入了这3个参数，
这样就可以得到不同的细微差别的复杂对象了。

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