C++观察者模式

落日映苍穹つ 2022-08-28 01:55 149阅读 0赞

头文件：

#ifndef COBSERVERMODE_H
    #define COBSERVERMODE_H
    
    #include<QDebug>
    #include <iostream>
    #include<string>
    #include <vector>
    using namespace std;
    
    #define cout qDebug() << "[" << __FILE__ << ":" << __LINE__ << ":" << __func__ << "]"
    
    
    /*
    定义对象间的一种一对多的依赖关系，当一个对象的状态发生改变时，所有依赖于它的对象都得到通知并被自动更新。
    说明：将观察者聚集到被观察者韩非子身边，韩非子的每一个举动都会通知给观察者，如李斯或周斯。
    注意：最多允许一个对象既是观察者也是被观察者。就像数据库中的触发器一样，成为一个复杂的链就很难维护了。观察者类似于委托的处理方式。
    */
    
    
    
    class CObserverMode
    {
        
    public:
        CObserverMode();
    };
    
    class IObserver;
    
    //被观察者接口
    class IObservable
    {
        
    public:
        IObservable(void)
        {
        
        }
        virtual ~IObservable(void)
        {
        
        }
        virtual void AddObserver(IObserver *pObserver) = 0;
        virtual void DeleteObserver(IObserver *pObserver) = 0;
        virtual void NotifyObservers(string context) = 0;
    };
    
    
    //被观察者1-韩非子
    class CHanFeiziObservable :
        public IObservable
    {
        
    public:
        CHanFeiziObservable(void);
        ~CHanFeiziObservable(void);
        void AddObserver(IObserver *pObserver);
        void DeleteObserver(IObserver *pObserver);
        void NotifyObservers(string context);
        void HaveBreakfast();
        void HaveFun();
    private:
        vector<IObserver*> m_observerList;
        typedef vector<IObserver*>::const_iterator ObserverList_C_iterator;
    };
    //观察者接口
    class IObserver
    {
        
    public:
        IObserver(string _name)
        {
        
            this->m_name = _name;
        }
        virtual ~IObserver(void)
        {
        
        }
        virtual void Update(string context) = 0;
        virtual string GetName() = 0;//为c++单独增加的函数，用于删除时查找观察者。
    protected:
        string m_name;
    };
    //观察者1
    class CLiSiObserver :
        public IObserver
    {
        
    public:
        CLiSiObserver(void);
        ~CLiSiObserver(void);
        void Update(string context);
        string GetName();
    private:
        void ReportToQinShiHuang(string report);
    };
    
    //观察者2
    class CZhouSiObserver :
        public IObserver
    {
        
    public:
        CZhouSiObserver(void);
        ~CZhouSiObserver(void);
        void Update(string context);
        string GetName();
    private:
        void Cry(string report);
    };
    
    
    void ObserverTest();
    #endif // COBSERVERMODE_H

源文件：

#include "cobservermode.h"
    
    CObserverMode::CObserverMode()
    {
        
    
    }
    CHanFeiziObservable::CHanFeiziObservable(void)
    {
        
    }
    CHanFeiziObservable::~CHanFeiziObservable(void)
    {
        
    }
    void CHanFeiziObservable::AddObserver( IObserver *pObserver )
    {
        
        m_observerList.push_back(pObserver);
    }
    void CHanFeiziObservable::DeleteObserver( IObserver *pObserver )
    {
        
        ObserverList_C_iterator it = m_observerList.begin();
        for (; it != m_observerList.end(); it++)
        {
        
            string name = (*it)->GetName();
            if (name.compare(pObserver->GetName()) == 0)
            {
        
                //找到了删除。
            }
        }
    }
    void CHanFeiziObservable::NotifyObservers( string context )
    {
        
        ObserverList_C_iterator it = m_observerList.begin();
        for (; it != m_observerList.end(); it ++)
        {
        
    
            (*it)->Update(context);
        }
    }
    void CHanFeiziObservable::HaveBreakfast()
    {
        
        cout << "韩非子：开始吃饭了..." << endl;
        this->NotifyObservers("韩非子在吃饭");
    }
    void CHanFeiziObservable::HaveFun()
    {
        
        cout << "韩非子：开始娱乐了..." << endl;
    
        this->NotifyObservers("韩非子在娱乐");
    }
    //
    CLiSiObserver::CLiSiObserver(void) : IObserver("李斯")
    {
        
    }
    CLiSiObserver::~CLiSiObserver(void)
    {
        
    }
    void CLiSiObserver::Update( string context )
    {
        
        cout << "李斯：观察到韩非子活动，开始向老板汇报了..." << endl;
        this->ReportToQinShiHuang(context);
        cout << "李斯：汇报完毕，秦老板赏给他两个萝卜吃吃..." << endl;
    }
    void CLiSiObserver::ReportToQinShiHuang( string report )
    {
        
        cout << "李斯：报告，秦老板！韩非子有活动了--->" << report.c_str() << endl;
    }
    string CLiSiObserver::GetName()
    {
        
        return m_name;
    }
    /
    CZhouSiObserver::CZhouSiObserver(void) : IObserver("周斯")
    {
        
    }
    CZhouSiObserver::~CZhouSiObserver(void)
    {
        
    }
    void CZhouSiObserver::Update( string context )
    {
        
        cout << "周斯：观察到韩非子活动，自己也开始活动了..." << endl;
        this->Cry(context);
        cout << "周斯：真真的哭列了..." << endl;
    }
    void CZhouSiObserver::Cry( string report )
    {
        
        cout << "周斯：为因" << report.c_str() << ", ————所以我悲伤呀！" << endl;
    }
    string CZhouSiObserver::GetName()
    {
        
        return m_name;
    }
    //使用测试
    static void DoNew()
    {
        
        //IHanFeiZi.h, HanFeiZiNew.h, ILiSi.h, LiSi.h
        // cout << "----------用新的方法试试----------" << endl;
    
        CHanFeiziObservable hanfeizi;
        hanfeizi.HaveBreakfast();
        hanfeizi.HaveFun();
    }
    
    static void DoNewNew()
    {
        
        //IObservable.h, HanfeiziObservable.h, IObserver.h, LiSiObserver.h
        cout << "----------用更新的方法再试试----------" << endl;
        //观察者
        IObserver *pLiSi = new CLiSiObserver();
        IObserver *pZhouSi = new CZhouSiObserver();
    
        //被观察者
        CHanFeiziObservable *pHanFeiZi = new CHanFeiziObservable();
    
        pHanFeiZi->AddObserver(pLiSi);
        pHanFeiZi->AddObserver(pZhouSi);
        pHanFeiZi->HaveBreakfast();
    
        delete pLiSi;
        pLiSi = NULL;
        delete pHanFeiZi;
        pHanFeiZi = NULL;
    }
    
    
    
    void ObserverTest()
    {
        
        DoNewNew();
    }