Python设计模式

#可以继承一个抽象类
class Observer():
    """观察者基类"""

    # @abstractmethod
    def update(self, observable, object):
        pass


class Observable:
    """被观察者的基类"""

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

    def addObserver(self, observer):
        self.__observers.append(observer)

    def removeObserver(self, observer):
        self.__observers.remove(observer)

    def notifyObservers(self, object):
        for obj in self.__observers:
            obj.update(self, object)

‘‘‘
举例:异地登录提醒
‘‘‘
import time

class Account(Observable):
    def __init__(self):
        super().__init__()
        self.__lastIp = {}
        self.__lastRegion = {}

    def __getRegion(self, ip):
        #由IP地址获取地区信息。这里只是模拟，真实项目中应该调用IP地址解析服务。
        ipRegions = {
            "101.47.18.9":"浙江杭州",
            "67.218.147.69":"美国洛杉矶",
        }
        # region = ipRegions[ip]
        region = ipRegions.get(ip)
        return "" if region is None else region

    def __isLongDistance(self, name, region):
        # 计算本次登录与最近几次登录的距离
        # 真实项目中调用地理信息相关服务
        lastRegion = self.__lastRegion.get(name)
        return lastRegion is not None and lastRegion != region

    def login(self, name, ip, time):
        region = self.__getRegion(ip)
        if self.__isLongDistance(name, region):
            self.notifyObservers({"name":name,"ip":ip,"region":region,"time":time})
        self.__lastRegion[name] = region
        self.__lastIp[name] = ip

class SmsSender(Observer):
    def update(self, observable, object):
        print("[短信发送] " + object["name"] + "您好！检测到您的账户可能登录异常。最近一次登录信息：\n"
              + "登录地区：" + object["region"] + "  登录ip：" + object["ip"] + "  登录时间："
              + time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(object["time"])))

class MailSender(Observer):
    """邮件发送器"""

    def update(self, observable, object):
        print("[邮件发送] " + object["name"] + "您好！检测到您的账户可能登录异常。最近一次登录信息：\n"
              + "登录地区：" + object["region"] + "  登录ip：" + object["ip"] + "  登录时间："
              + time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(object["time"])))

if "__main__" == __name__:
    accout = Account()
    accout.addObserver(SmsSender())
    accout.addObserver(MailSender())
    accout.login("Tony", "101.47.18.9", time.time())
    accout.login("Tony", "67.218.147.69", time.time())