#include<iostream>
#include<list>
#include<string>
#include<type_traits>
#include<functional>
using namespace std;
using namespace std::placeholders;
struct metadata
{
int Temperature;
int humidity;
int pressure;
};
class Display {
public:
// virtual ~Display () = 0;
virtual void Update(const metadata& data) = 0;
virtual std::string& GetName() { return m_name; };
virtual void SetName(const std::string& name) { m_name = name; };
virtual void callback(metadata& data);
private:
std::string m_name;
};
class Temperature : public Display
{
public:
Temperature() {
SetName("Temperature");
};
~Temperature() {};
void Update(const metadata& data) override;
};
void Temperature::Update(const metadata& data)
{
std::cout << " Temperature: " << data.Temperature << std::endl;
}
class Humidity : public Display
{
public:
Humidity() {
SetName("Humidity");
};
~Humidity() {};
void Update(const metadata& data) override;
};
void Humidity::Update(const metadata& data)
{
std::cout << " Humidity: " << data.humidity << std::endl;
}
using DataCB = std::function<void(metadata& data)>;//申明指针类型
//数据端
class BaseData{
public:
BaseData();
void notify(metadata& data);
void SetWeatherData(WeatherData* data){m_weatherdata = data;};
metadata m_data;
WeatherData* m_weatherdata;
};
BaseData::BaseData()
{
}
void BaseData::notify(metadata& data)
{
m_weatherdata->update(data);
}
class WeatherData
{
public:
WeatherData();
~WeatherData() {};
void Init();
void Update();//通知每一个订阅者
void AddSubscriber(Display* subscriber);//添加订阅者
void RemoveSubscriber(Display* subscriber);//移除订阅者
void ADDregistercb(DataCB cb){
m_ldataCB.push_back(cb);
}
void notify(metadata& data)
{
for(auto& cb : m_ldataCB)
{
cb(data);
}
}
private:
std::list<Display*> m_observers;
metadata m_data;//下一步添加回调函数来通知修改数据，修改数据在通知display
std::list<DataCB> m_ldataCB;
};
void WeatherData::Init()
{
}
WeatherData::WeatherData()
{
m_data.Temperature = 10;
m_data.humidity = 20;
m_data.pressure = 30;
}
void WeatherData::AddSubscriber(Display* subscriber)
{
auto it = m_observers.begin();
for (; it != m_observers.end(); it++)//防止同一类型的订阅者重复订阅
{
std::cout << " obsername : " << (*it)->GetName() << " subscriber : " << subscriber->GetName()<<std::endl;
if ((*it)->GetName() == subscriber->GetName())//之前订阅过
{
break;
}
}
m_observers.push_back(subscriber);
}
void WeatherData::Update()
{
for (auto& observer : m_observers)
{
observer->Update(m_data);
}
}
void WeatherData::RemoveSubscriber(Display* subscriber)
{
for (auto& observer : m_observers)
{
std::cout << observer->GetName() << std::endl;
if ((*observer).GetName() == subscriber->GetName())
{
m_observers.remove(observer);
return ;
}
}
}
weatherData->ADDregistercb(std::bind(&Display::callback,t,std::placeholders::_1)); weatherData->ADDregistercb(std::bind(&Display::callback,hum,std::placeholders::_1)); adata->SetWeatherData(weatherData); adata->notify(data);
// } // else if (str == "0h") // { // weatherData.RemoveSubscriber(hum); // } // weatherData.Update(); // } // } return 0; } 标签：std,WeatherData,void,观察者,模式,data,Display,metadata From： https://www.cnblogs.com/intdouble/p/18402775