设计模式之桥接模式

桥接模式(Bridge)属于结构模式，桥接模式提供了一种灵活应对变化的方法，它通过把抽象类和它的实现这种上下的耦合关系转换成聚合的关系，也就是具体实现是独立实现的，而抽象类拥有对它的引用，这样，如果需要扩充实现类的功能，这个时候又不能违背单一职责准则，则只需要在抽象类的实现里面增加新的功能即可。
下面是桥接模式的C++实现，代码可到本人github网页下载：设计模式例子

/* * Example of 'Bridge' design pattern. * Copyright (C) 2016 Leo Wang * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */#include <iostream>using namespace std;class CImplement{    public:        virtual void GeneralFunc()=0;};class CConcreteImplementA:public CImplement{    public:        void GeneralFunc()        {            cout<<"General func type A!"<<endl;        };};class CConcreteImplementB:public CImplement{    public:        void GeneralFunc()        {            cout<<"General func type B!"<<endl;        };};class CAbstract{    public:        CImplement* cp_impl;    public:        virtual void SpecialFunc()=0;    public:        CAbstract(CImplement* p_impl)        {            cp_impl=p_impl;        };};class CConcreteAbstract:public CAbstract{    public:        void SpecialFunc()        {            cout<<"Special func!"<<endl;            cp_impl->GeneralFunc();        }    public:        CConcreteAbstract(CImplement* p_impl):CAbstract(p_impl)    {};};int main(){    CImplement* cp_impA=new CConcreteImplementA();    CImplement* cp_impB=new CConcreteImplementB();    CAbstract* cp_abstractA=new CConcreteAbstract(cp_impA);    CAbstract* cp_abstractB=new CConcreteAbstract(cp_impB);    cp_impA->GeneralFunc();    cp_impB->GeneralFunc();    cp_abstractA->SpecialFunc();    cp_abstractB->SpecialFunc();    return 1;};