c++/qt设计模式-适配器模式

文章中部分内容和思路来自《Head First设计模式》

模式定义

将一个类的接口，转换成客户期望的另一个接口。适配器让原本接口不兼容的类可以合作无间

模式类图

1.对象适配器：



2.类适配器：



[ps：对象适配器和类适配器使用了两种不同的适配方式，对象适配器使用组合实现适配，类适配器使用继承实现适配]

典型案例

1.案例需求
不同国家的充电头和插座的设计标准不同，例如中国采用两孔扁平的插头和插座，而德国习惯使用三孔圆形插头。假设你只带了两孔扁平的插头去德国出差，而所住的旅馆只有三孔圆形的插头，设计一种方式不改变现有条件的情况下给手机充电。

2.情况分析



如图，我们需要一个额外的设备，该设备需要有两孔扁平插头的插孔(接口)同时也要有三孔圆形插头。

3.代码实现
-------------------
DBSocketInterface.h

-------------------#ifndef DBSOCKETINTERFACE_H

#define DBSOCKETINTERFACE_H

class DBSocketInterface

{

public:

virtual void powerByRound() = 0;

};

#endif // DBSOCKETINTERFACE_H

 
-------------------
GBSocketInterface.h
-------------------#ifndef GBSOCKETINTERFACE_H

#define GBSOCKETINTERFACE_H

class GBSocketInterface

{

public:

virtual void powerByFlat() = 0;

};

#endif // GBSOCKETINTERFACE_H

 
----------
DBSocket.h
----------#ifndef DBSOCKET_H

#define DBSOCKET_H

#include "dbsocketinterface.h"

class DBSocket : public DBSocketInterface

{

public:

DBSocket();

public:

virtual void powerByRound();

};

#endif // DBSOCKET_H

 
------------
DBSocket.cpp
------------#include "DBSocket.h"

#include <QDebug>

DBSocket::DBSocket()

{

}

void DBSocket::powerByRound()

{

qDebug() << "power by round.";

}

 
----------
GBSocket.h
----------#ifndef GBSOCKET_H

#define GBSOCKET_H

#include "GBSocketInterface.h"

class GBSocket : public GBSocketInterface

{

public:

GBSocket();

public:

virtual void powerByFlat();

};

#endif // GBSOCKET_H

 
------------
GBSocket.cpp
------------#include "GBSocket.h"

#include <QDebug>

GBSocket::GBSocket()

{

}

void GBSocket::powerByFlat()

{

qDebug() << "power by flat.";

}

 
-------
Hotel.h
-------#ifndef HOTEL_H

#define HOTEL_H

#include "DBSocketInterface.h"

class Hotel

{

public:

Hotel(DBSocketInterface *socket);

public:

void powerForGBMobile(); // 给手机充电

public:

DBSocketInterface *_dbSocket; // 只有圆头

};

#endif // HOTEL_H

 
---------
Hotel.cpp
---------#include "Hotel.h"

Hotel::Hotel(DBSocketInterface *dbSocket)

{

_dbSocket = dbSocket;

}

void Hotel::powerForGBMobile()

{

_dbSocket->powerByRound(); // 看起来使用圆头充电

}

 
-------------------
Round2FlatAdaptor.h
-------------------#ifndef ROUND2FLATADAPTOR_H

#define ROUND2FLATADAPTOR_H

#include "GBSocketInterface.h"

#include "dbsocketinterface.h"

class Round2FlatAdaptor : public DBSocketInterface

{

public:

Round2FlatAdaptor(GBSocketInterface *gbSocket);

public:

virtual void powerByRound();

private:

GBSocketInterface *_gbSocket;

};

#endif // ROUND2FLATADAPTOR_H

 
---------------------
Round2FlatAdaptor.cpp
---------------------#include "Round2FlatAdaptor.h"

Round2FlatAdaptor::Round2FlatAdaptor(GBSocketInterface *gbSocket)

{

_gbSocket = gbSocket;

}

void Round2FlatAdaptor::powerByRound()

{

_gbSocket->powerByFlat();

}

 
--------
main.cpp
--------/**

* 设计模式-适配器模式

* 要点：1,已有接口(dbsocket) 2,目标接口(gbsocket) 3,适配器(与已有接口有共同超类,实现依赖目标接口)

*/

#include <QCoreApplication>

#include "Hotel.h"

#include "GBSocket.h"

#include "Round2FlatAdaptor.h"

int main(int argc, char *argv[])

{

QCoreApplication a(argc, argv);

GBSocket socket;

Hotel hotel(new Round2FlatAdaptor(&socket)); // Hotel hotel; hotel.setSocket(dbSocket);

hotel.powerForGBMobile();

return a.exec();

}