python理解观察者模式（发布——订阅者模式）

# -*- coding: utf-8 -*-



class Subject:

    def register(self, observer):
        pass

    def unregister(self, observer):
        pass

    def notify(self, msg):
        pass


class Weather(Subject):

    def __init__(self):
        self.observers = []

    def register(self, observer):
        if not observer in self.observers:
            self.observers.append(observer)

    def unregister(self, observer):
        self.observers.remove(observer)

    def notify(self, msg):
        for observer in self.observers:
            observer.do_something(msg)


class Observer:

    def do_something(self, msg):
        pass


class Ruhua(Observer):

    def do_something(self, msg):
        if '雨' in msg:
            print('下雨了，如花可以去桥边等伯虎了')
        elif '雪' in msg:
            print('下雪了，如花可以去堆雪人了')
        elif '太阳' in msg:
            print('出太阳了，如花要去网吧了')


class Cuihua(Observer):

    def do_something(self, msg):
        if '雨' in msg:
            print('下雨了，翠花要做酸菜了')
        elif '雪' in msg:
            print('下雪了，翠花要喂雪人吃酸菜了')
        elif '太阳' in msg:
            print('出太阳了，翠花，上酸菜')


class Cunhua(Observer):

    def do_something(self, msg):
        if '雨' in msg:
            print('下雨了，村花在赏雨')
        elif '雪' in msg:
            print('下雪了，村花在赏雪')
        elif '太阳' in msg:
            print('出太阳了，村花在日光浴')


if __name__ == '__main__':
    ruhua = Ruhua()
    cuihua = Cuihua()
    cunhua = Cunhua()

    weather = Weather()
    weather.register(ruhua)
    weather.register(cuihua)
    weather.register(cunhua)

    weather.notify('下雨了')
    weather.notify('出太阳了')
    weather.notify('下雪了')

来源：CSDN

作者：浪子哥学习笔记

链接：https://blog.csdn.net/qq_36072270/article/details/104520143