学习笔记——建造者模式Builder

构造者模式。外部场景如果需要一个汽车类，它不需要关心如何构造，它只需要告诉Director需要什么，就可以从Director获得。

如：CDirector(IBuilder* aBuilder);

场景告诉Director它需要用什么类型的Builder来构造，然后就可以用Create()获得所创建的对象。

具体的构造由具体的Builder负责，当我们想变换创建方法时，变换传递的Builder实例就可以了。

C++示例

IBuilder.h

 #pragma once
 #include <string>
 using namespace std;

 class IBuilder
 {
 public:
     IBuilder(void);
     ~IBuilder(void);
 public:
     virtual void BuildA(const string& str)=;
     virtual void BuildB(const string& str)=;
 };

IBuilder.cpp

 #include "IBuilder.h"

 IBuilder::IBuilder(void)
 {
 }

 IBuilder::~IBuilder(void)
 {
 }

Builder.h

 #pragma once
 #include "ibuilder.h"

 class CBuilder :
     public IBuilder
 {
 public:
     CBuilder(void);
     ~CBuilder(void);
 public:
     void BuildA(const string& str);
     void BuildB(const string& str);
 };

Builder.cpp

 #include "Builder.h"
 #include <iostream>

 CBuilder::CBuilder(void)
 {
 }

 CBuilder::~CBuilder(void)
 {
 }

 void CBuilder::BuildA(const string& str)
 {
     std::cout<<"A:"<<str<<std::endl;
 }

 void CBuilder::BuildB(const string& str)
 {
     std::cout<<"B:"<<str<<std::endl;
 }

Director.h

 #pragma once
 #include "IBuilder.h"

 class CDirector
 {
 public:
     CDirector(IBuilder* aBuilder);
     ~CDirector(void);
 public:
     void Construct();
 private:
     IBuilder* mBuilder;
 };

Director.cpp

 #include "Director.h"

 CDirector::CDirector(IBuilder* aBuilder)
 {
     this->mBuilder = aBuilder;
 }

 CDirector::~CDirector(void)
 {
     delete mBuilder;
 }

 void CDirector::Construct()
 {
     this->mBuilder->BuildA("test");
     this->mBuilder->BuildB("hello");
 }

main.cpp

 #include <iostream>
 #include "Director.h"
 #include "Builder.h"

 int main()
 {
     CDirector* pDirector = new CDirector(new CBuilder());
     pDirector->Construct();
     return ;
 }

Tip:示例代码中没有使用Product。