在提出桥梁模式的时候指出，桥梁模式的用意是"将抽象化(Abstraction)与实现化(Implementation)脱耦，使得二者可以独立地变化"。这句话有三个关键词，也就是抽象化、实现化和脱耦。
抽象化
存在于多个实体中的共同的概念性联系，就是抽象化。作为一个过程，抽象化就是忽略一些信息，从而把不同的实体当做同样的实体对待【LISKOV94】。
实现化
抽象化给出的具体实现，就是实现化。
脱耦
所谓耦合，就是两个实体的行为的某种强关联。而将它们的强关联去掉，就是耦合的解脱，或称脱耦。在这里，脱耦是指将抽象化和实现化之间的耦合解脱开，或者说是将它们之间的强关联改换成弱关联。
将两个角色之间的继承关系改为聚合关系，就是将它们之间的强关联改换成为弱关联。因此，桥梁模式中的所谓脱耦，就是指在一个软件系统的抽象化和实现化之间使用组合/聚合关系而不是继承关系，从而使两者可以相对独立地变化。这就是桥梁模式的用意。
在使用VIM 编写makefile时，有时TAP键会是八个空格，使用set list命令可以查看所有的TAB键是否正确。
makefile文件
aLL:Brige
CC = g++
INCLUDE = .
CFLAGS = -g -Wall
Brige:main.o CDrawLine.o CDrawSquare.o CSqureRefined.o CCircleRefined.o
$(CC) -o Brige main.o CDrawLine.o CDrawSquare.o CSqureRefined.o CCircleRefined.o
CDrawSquare.o:CDrawSquare.cpp CDrawSquare.h CImplement.cpp
$(CC) -I$(INCLUDE) $(CFLAGS) -c CDrawSquare.cpp
CDrawLine.o:CDrawLine.cpp CDrawLine.h
$(CC) -I$(INCLUDE) $(CFLAGS) -c CDrawLine.cpp
CSqureRefined.o:CSqureRefined.cpp CSqureRefined.h
$(CC) -I$(INCLUDE) $(CFLAGS) -c CSqureRefined.cpp
CCircleRefined.o:CCircleRefined.cpp CCircleRefined.h
$(CC) -I$(INCLUDE) $(CFLAGS) -c CCircleRefined.cpp
main.o:main.cpp
$(CC) -I$(INCLUDE) $(CFLAGS) -c main.cpp
clean:
rm *.o
rm Brige
CAbstraction.h
#ifndef CAbstractiongH
#define CAbstractiongH
#include<iostream>
#include "CImplement.h"
using namespace std;
class CAbstractiong
{
public:
virtual ~CAbstractiong(){};
virtual void Operation() = 0;
void SetImplement(CImplement *tImplement){m_CImplement = tImplement;};
protected:
CAbstractiong(){};
CImplement *m_CImplement;
};
#endif
CCircleRefined
#ifndef CCircleRefinedH
#define CCircleRefinedH
#include "CAbstraction.h"
class CCircleRefined:public CAbstractiong
{
public:
CCircleRefined(){};
~CCircleRefined(){};
void Operation();
};
#endif
#include "CCircleRefined.h"
void CCircleRefined::Operation()
{
cout<<"对圆形进行了"<<m_CImplement->Operation()<<endl;
}
CSqureRefined
#ifndef CSqureRefinedH
#define CSqureRefinedH
#include "CAbstraction.h"
class CSqureRefined:public CAbstractiong
{
public:
CSqureRefined(){};
~CSqureRefined(){};
void Operation();
};
#endif
#include "CSqureRefined.h"
void CSqureRefined::Operation()
{
cout<<"对正方形进行了"<<m_CImplement->Operation()<<endl;
}
CAbstractiong
#ifndef CAbstractiongH
#define CAbstractiongH
#include<iostream>
#include "CImplement.h"
using namespace std;
class CAbstractiong
{
public:
virtual ~CAbstractiong(){};
virtual void Operation() = 0;
void SetImplement(CImplement *tImplement){m_CImplement = tImplement;};
protected:
CAbstractiong(){};
CImplement *m_CImplement;
};
#endif
CDrawSquare
#ifndef CDrawSquareH
#define CDrawSquareH
#include<iostream>
#include "CImplement.h"
class CDrawSquare:public CImplement
{
public:
CDrawSquare(){};
~CDrawSquare(){};
string Operation();
};
#endif
#include "CDrawSquare.h"
#include <iostream>
using namespace std;
string CDrawSquare::Operation()
{
string sTemp ="进行了画方格操作";
return sTemp;
}
CDrawLine
#ifndef CDrawLineH
#define CDrawLineH
#include<iostream>
#include <string>
#include "CImplement.h"
class CDrawLine:public CImplement
{
public:
CDrawLine(){};
~CDrawLine(){};
string Operation();
};
#endif
#include "CDrawLine.h"
#include <iostream>
using namespace std;
string CDrawLine::Operation()
{
string sTemp = "进行了画线操作";
return sTemp;
}
main.cpp
#include "CDrawLine.h"
#include "CDrawSquare.h"
#include "CSqureRefined.h"
#include "CCircleRefined.h"
int main()
{
CDrawLine *pCDrawLine = new CDrawLine();
CCircleRefined *pCCircleRefined = new CCircleRefined();
pCCircleRefined->SetImplement(pCDrawLine);
pCCircleRefined->Operation();
CDrawSquare *pCDrawSquare = new CDrawSquare();
pCCircleRefined->SetImplement(pCDrawSquare);
pCCircleRefined->Operation();
return 0;
}