设计模式----观察者模式

Posted 2022-12-07 幻觉czw

#设计模式---观察者模式
#纯属练手仿制，如有错误欢迎拍砖
#delusion's code
#气象站台---小试牛刀
class Subject(object):#被观察的对象
    def register(self,observer):
        pass

    def unregister(self,observer):#移除观察者
        pass

    def notify(self):#通知观察者
        pass
#观察者
class Observer(object):
    def update(self,temperature,humidity,pressure):
        pass

class Display(object):
    def display(self):
        pass

class Weather_data(Subject):
    def __init__(self):
        self.observers = []

    def register(self,observer):#注册观察者
        if observer not in self.observers:
            self.observers.append(observer)

    def unregister(self,observer):#移除观察者
        if observer in self.observers:
            self.observers.remove(observer)

    def date_change(self):#当数据发生改变时，通知观察者
        for o in self.observers:
            o.update(self.temperature,self.humidity,self.pressure)#调用观察者的更新方法

    def notify(self):#通知观察者
        self.date_change()

    def setdata(self,temperature = None,humidity = None,\\  #数据改变
                pressure = None):
        self.temperature = temperature
        self.humidity = humidity
        self.pressure = pressure
        self.notify()

class CurrentDisplay(Observer,Display):#定义了一个事实更新的观察者
    def __init__(self,weather_data = None):
        self.weather_data = weather_data
        weather_data.register(self)

    def update(self,temperature,humidity,pressure):#更新得到的数据
        self.temperature = temperature
        self.humidity = humidity
        self.pressure = pressure
        self.display()

    def display(self):#显示更新
        print 'Current data : temperature == %s, humidity == %s, pressure == %s' \\
              % (self.temperature,self.humidity,self.pressure)

class AverageDisplay(Observer,Display):
    def __init__(self,weather_data = None):
        self.weather_data = weather_data
        weather_data.register(self)
        self.temperatures = []
        self.humidities = []
        self.pressures = []

    def update(self,temperature,humidity,pressure):
        self.temperatures.append(temperature)
        self.humidities.append(humidity)
        self.pressures.append(pressure)
        self.display()

    def average(self,datas):
        sum = 0
        for i in datas:
            sum += i
        return sum/len(datas)

    def display(self):
        print 'Average data: temperature == %s,humidity == %s,pressure == %s'\\
              % (self.average(self.temperatures),self.average(self.humidities)\\
                 ,self.average(self.pressures))