C++：2.工厂模式

工厂模式主要解决同一类接口不同厂家有不同实现这类问题。以业务集成相机sdk为例相机常用到的功能有打开相机、读取流、关闭流、设置相机参数等。但不同厂家sdk实现方式不一样如果不用工厂模式那相同的业务代码可能要写很多份。使用后整体代码变得简洁耦合性好。下面举例说明。1.抽象相机基类基类中通常包含两类接口一类是通用接口这类接口和相机厂家无关但相机创建时候又都会用到。另一类是纯虚函数接口这类接口就是相机相关操作的抽象如打开相机等。基类头文件#ifndef _ICAMERA_H_ #define _ICAMERA_H_ #include string #include map class ICamera { public: ICamera(std::string cameraName) :name(cameraName) {}; /** * brief 加载本地图片仿真使用 * param cameraName * param simPicDir */ ICamera(std::string cameraName, std::string picDir); virtual ~ICamera() default; /*************************相机厂家重写*************************/ /** * brief 相机初始化 * return */ virtual void init(CameraManagePara cmPara) 0; /** * brief 设置相机参数 * param para * return */ virtual bool setParameter(CameraThreadPara para) 0; /** * brief 相机在线状态 * return */ virtual bool isOnline() 0; /** * brief 句柄是否有效 * return */ virtual bool isValidHandle() 0; /** * brief 关闭相机 */ virtual void close() 0; /** * brief 关闭流 * param */ virtual void stopGrab() 0; /*************************基类通用接口-厂家不需要实现*************************/ /** * brief 获取相机名称 * return */ std::string getCameraName(); /** * brief 可以抽取出来的通用逻辑 * return */ void commonFun(std::string picDir); public: /** * brief 通用成员变量 */ uint64_t frameTime 0; uint64_t frameId 0; /** * brief 相机名称 */ std::string name; }; #endif // !_ICAMERA_H_基类源文件#include ICamera.h ICamera::ICamera(std::string cameraName, std::string picDir) { name cameraName; commonFun(picDir); } std::string ICamera::getCameraName() { return name; } void ICamera::commonFun(std::string picDir) { //业务逻辑 }2.具体相机子类这里只举例一个厂家如果多个厂家写多个子类就行。头文件#ifndef _DSCAMERA_H_ #define _DSCAMERA_H_ #include ICamera.h #include DVPCamera.h class DSCamera : public ICamera { public: ~DSCamera() override { close(); } DSCamera(std::string cameraName, std::string simPicDir) : ICamera(cameraName, simPicDir) {} /** * brief 相机初始化 * return */ virtual void init(CameraManagePara cmPara) override; /** * brief 设置相机参数 * param para * return */ virtual bool setParameter(CameraThreadPara para) override; /** * brief 相机在线状态 * return */ virtual bool isOnline() override; /** * brief 句柄是否有效 * return */ virtual bool isValidHandle() override; /** * brief 关闭相机 */ virtual void close() override; /** * brief 关闭流 * param */ virtual void stopGrab() override; private: //bool isValidHandle(); void connect(CameraManagePara cmPara); //相机原生句柄 dvpHandle handle; }; #endif // !_DSCAMERA_H_源文件#include DSCamera.h dvpInt32 dSCameraCallBack(dvpHandle handle, dvpStreamEvent event, void* pContext, dvpFrame* pFrame, void* pBuffer) { DSCamera* pThis (DSCamera*)pContext; //基类通用变量 pThis-frameId pFrame-uFrameID; //回调取图 cv::Mat mat cv::Mat(pFrame-iHeight, pFrame-iWidth, CV_8UC3, (uchar*)pBuffer, pFrame-iWidth * 3).clone(); return 0; } void DSCamera::init(CameraManagePara cmPara) { connect(cmPara); } bool DSCamera::setParameter(CameraThreadPara para) { dvpStatus status; //关闭流 status dvpStop(handle); //设置相机参数等等 //开启流 status dvpStart(handle); return true; } bool DSCamera::isOnline() { if (!isValidHandle()) return false; dvpStatus status; bool online false; status dvpIsOnline(handle, online); if (status ! DVP_STATUS_OK) { LOG(ERROR) get online status error std::endl; return false; } return online; } void DSCamera::close() { //关闭视频流 dvpStatus status dvpStop(handle); //关闭相机 dvpStatus status1 dvpClose(handle); } bool DSCamera::isValidHandle() { bool isValid false; dvpStatus status dvpIsValid(handle, isValid); if (status ! DVP_STATUS_OK) { return false; } return isValid; } void DSCamera::stopGrab() { dvpStatus status dvpStop(handle); } void DSCamera::connect(CameraManagePara cmPara) { dvpStatus status; status dvpOpenByUserId(name.c_str(), OPEN_NORMAL, handle); //设置相机属性-略 //设置回调 status dvpRegisterStreamCallback(handle, dSCameraCallBack, STREAM_EVENT_FRAME_THREAD, this); }3.抽象工厂通过工厂来创建具体子类对象。#ifndef _ICAMERAFACTORY_H_ #define _ICAMERAFACTORY_H_ #include ICamera.h #include DSCamera.h #include DHCamera.h #include MDWSCamera.h class ICameraFactory { public: virtual ~ICameraFactory() default; // 创建对应厂商相机实例 virtual ICamera* createCamera(std::string cameraName, std::string picPath) 0; }; class DSCameraFactory : public ICameraFactory { public: ICamera* createCamera(std::string cameraName, std::string picPath) override { return new DSCamera(cameraName, picPath); } }; class DHCameraFactory : public ICameraFactory { public: ICamera* createCamera(std::string cameraName, std::string picPath) override { return new DHCamera(cameraName, picPath); } }; class MDWSCameraFactory : public ICameraFactory { public: ICamera* createCamera(std::string cameraName, std::string picPath) override { return new MDWSCamera(cameraName, picPath); } }; class CameraFactoryManager { public: // 根据相机类型创建相机实例 static ICamera* createCamera(const std::string camType, const std::string camName, const std::string picPath) { if (camType DS) { return DSCameraFactory{}.createCamera(camName, picPath); } else if (camType DH) { return DHCameraFactory{}.createCamera(camName, picPath); } else if (camType MDWS) { MDWSCameraFactory factory; return MDWSCameraFactory{}.createCamera(camName, picPath); } else { throw std::runtime_error(unsupported camera type: camType); } } }; #endif // !_ICAMERAFACTORY_H_