设计模式之桥接模式

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桥接模式

特点：

多对多的关系（多维元素在变化），仅用继承实现不太合理。Bridge用于将表示和实现解耦,两者可以独立的变化.

角色：

Abstraction::Operation()：定义要实现的操作接口。在Abstraction类中维护一个Implement类指针（成员变量）,需要采用不同的实现方式的时候只需要传入不同的Implement派生类就可以了。

Implement::OperationImp()

RefinedAbstraction::Operation()

ConcreteImplement::OperationImp()

桥接就是实现Operation()的定义（在Abstraction中）和Operation()的实现（在Implement中）实现解耦和。

class Engine;
class Car{//Abstraction
public:
Car(Engine* en){
m_en=en;
}
virtual void installEngine()=0;
protected:
Engine* m_en;

};
class Engine{//Implement
public:
virtual void InstallEngine()=0;
};
class Engine4400:public Engine{//ConcreteImplement
public:
void InstallEngine(){

cout<<"Install 4400 engine."<<endl;
}
};
class Engine4300:public Engine{
public:
void InstallEngine(){

cout<<"Install 4300 engine."<<endl;
}
};
class BM:public Car{//RefinedAbstraction

public:
BM(Engine* en):Car(en){}//子类的构造函数
void installEngine(){
cout<<"we are BM."<<endl;
m_en->InstallEngine();
}
};
class Jeep:public Car{

public:
Jeep(Engine* en):Car(en){}//子类的构造函数
void installEngine(){
cout<<"we are Jeep."<<endl;
m_en->InstallEngine();
}
};

int main(){
Car* car=NULL;
Engine* p=NULL;
p=new Engine4400;
car=new BM(p);
car->installEngine();
delete car;
delete p;
cout<<"-----------------------------"<<endl;
p=new Engine4300;
car=new Jeep(p);
car->installEngine();
delete p;
delete car;
return 0;
}