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)=0;
    virtual void BuildB(const string& str)=0;
};

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 0;
}

Tip:示例代码中没有使用Product。