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

 1 #pragma once
 2 #include <string>
 3 using namespace std;
 4 
 5 class IBuilder
 6 {
 7 public:
 8     IBuilder(void);
 9     ~IBuilder(void);
10 public:
11     virtual void BuildA(const string& str)=0;
12     virtual void BuildB(const string& str)=0;
13 };

IBuilder.cpp

 1 #include "IBuilder.h"
 2 
 3 
 4 IBuilder::IBuilder(void)
 5 {
 6 }
 7 
 8 
 9 IBuilder::~IBuilder(void)
10 {
11 }

Builder.h

 1 #pragma once
 2 #include "ibuilder.h"
 3 
 4 class CBuilder :
 5     public IBuilder
 6 {
 7 public:
 8     CBuilder(void);
 9     ~CBuilder(void);
10 public:
11     void BuildA(const string& str);
12     void BuildB(const string& str);
13 };

Builder.cpp

 1 #include "Builder.h"
 2 #include <iostream>
 3 
 4 CBuilder::CBuilder(void)
 5 {
 6 }
 7 
 8 
 9 CBuilder::~CBuilder(void)
10 {
11 }
12 
13 void CBuilder::BuildA(const string& str)
14 {
15     std::cout<<"A:"<<str<<std::endl;
16 }
17 
18 void CBuilder::BuildB(const string& str)
19 {
20     std::cout<<"B:"<<str<<std::endl;
21 }

Director.h

 1 #pragma once
 2 #include "IBuilder.h"
 3 
 4 class CDirector
 5 {
 6 public:
 7     CDirector(IBuilder* aBuilder);
 8     ~CDirector(void);
 9 public:
10     void Construct();
11 private:
12     IBuilder* mBuilder;
13 };

Director.cpp

 1 #include "Director.h"
 2 
 3 
 4 CDirector::CDirector(IBuilder* aBuilder)
 5 {
 6     this->mBuilder = aBuilder;
 7 }
 8 
 9 
10 CDirector::~CDirector(void)
11 {
12     delete mBuilder;
13 }
14 
15 void CDirector::Construct()
16 {
17     this->mBuilder->BuildA("test");
18     this->mBuilder->BuildB("hello");
19 }

main.cpp

 1 #include <iostream>
 2 #include "Director.h"
 3 #include "Builder.h"
 4 
 5 int main()
 6 {
 7     CDirector* pDirector = new CDirector(new CBuilder());
 8     pDirector->Construct();
 9     return 0;
10 }

Tip:示例代码中没有使用Product。