Bridge设计模式

来源：互联网发布：手机淘宝看退款率编辑：程序博客网时间：2024/06/10 20:04

一篇不错的文章http://blog.csdn.net/hguisu/article/details/7529194

文章中以将毛笔大小和颜色分开实现为实例阐述了Bridge模式的优点。作者给出的是PHP实现代码，这里给出C++实现代码！

BrushPenAbstraction.h

#ifndef _BRUSHPENABSTRACTION_H_#define _BRUSHPENABSTRACTION_H_class ImplementorColor;class BrushPenAbstraction{public:BrushPenAbstraction();virtual ~BrushPenAbstraction();virtual void OperationDraw() = 0;};//SmallBrushPenAbstractionclass SmallBrushPenAbstraction :public BrushPenAbstraction{public:SmallBrushPenAbstraction(ImplementorColor * color = 0){ m_color = color; }~SmallBrushPenAbstraction(){}void OperationDraw();private:ImplementorColor * m_color;};//MidBrushPenAbstractionclass MidBrushPenAbstraction :public BrushPenAbstraction{public:MidBrushPenAbstraction(ImplementorColor * color = 0){ m_color = color; }~MidBrushPenAbstraction(){}void OperationDraw();private:ImplementorColor * m_color;};//BigBrushPenAbstractionclass BigBrushPenAbstraction :public BrushPenAbstraction{public:BigBrushPenAbstraction(ImplementorColor * color = 0);~BigBrushPenAbstraction();void OperationDraw();private:ImplementorColor * m_color;};#endif

BrushPenAbstraction.cpp

#include "BrushPenAbstraction.h"#include "ImplementorColor.h"#include <iostream>//BrushPenAbstractionBrushPenAbstraction::BrushPenAbstraction(){}BrushPenAbstraction::~BrushPenAbstraction(){}//SmallBrushPenAbstractionvoid SmallBrushPenAbstraction::OperationDraw(){std::cout << "This is a small and ";m_color->OperationDraw();std::cout << " brush!\n";}//MidBrushPenAbstractionvoid MidBrushPenAbstraction::OperationDraw(){std::cout << "This is a middle and ";m_color->OperationDraw();std::cout << " brush!\n";}//BigBrushPenAbstractionBigBrushPenAbstraction::BigBrushPenAbstraction(ImplementorColor * color){m_color = color; }BigBrushPenAbstraction::~BigBrushPenAbstraction(){}void BigBrushPenAbstraction::OperationDraw(){std::cout << "This is a big and ";m_color->OperationDraw();std::cout << " brush!\n";}

ImplementorColor.h

#ifndef _IMPLEMENTORCOLOR_H_#define _IMPLEMENTORCOLOR_H_class ImplementorColor{public:ImplementorColor();virtual ~ImplementorColor();virtual void OperationDraw()=0;};//ImplementorRedclass ImplementorRed : public ImplementorColor{public:ImplementorRed();~ImplementorRed();void OperationDraw();};//ImplementorGreenclass ImplementorGreen : public ImplementorColor{public:ImplementorGreen();~ImplementorGreen();void OperationDraw();};//ImplementorBlueclass ImplementorBlue : public ImplementorColor{public:ImplementorBlue();~ImplementorBlue();void OperationDraw();};#endif

ImplementorColor

#include <iostream>#include "BrushPenAbstraction.h"#include "ImplementorColor.h"int main(){ImplementorColor * red = new ImplementorRed();ImplementorColor * blue = new ImplementorBlue();BrushPenAbstraction * bigBrush = new BigBrushPenAbstraction(red);bigBrush->OperationDraw();BrushPenAbstraction * midBrush = new MidBrushPenAbstraction(red);midBrush->OperationDraw();BrushPenAbstraction * smallBrush = new SmallBrushPenAbstraction(blue);smallBrush->OperationDraw();getchar();return 0;}

结果

C++ primer plus将继承描述为为一种 is-a 关系；而有元类是一种 has-a 关系，感觉Factory，Builder，包括这里的Bridge，可能还有更多我暂时没了解的设计模式，实现的也是一种has-a关系！

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