设计模式(python实现)--发布订阅者模式(Publiser)

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按照发布订阅者模式的思路，自己想了一个用例。类似于微信公众号，用户订阅某个公众号，公众号发布信息后，用户可以实时更新。简单版本如下：

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

class _PublisherManager(object):
    def __init__(self):
        self.publiser_objs_map = {}
        self.publiser_to_subscirber_map = {}

    def register_publiser(self, publiser_obj):
        if publiser_obj in self.publiser_objs_map:
            print('you have been registered before')
            return

        self.publiser_objs_map[publiser_obj] = []
        self.publiser_to_subscirber_map[publiser_obj] = []


    def publish_msg(self, publiser_obj, msg):
        if publiser_obj not in self.publiser_objs_map:
            print('please register and become a publiser before publish msg')
            return

        self.publiser_objs_map[publiser_obj].append(msg)
        subscriber_objs = self.publiser_to_subscirber_map[publiser_obj]
        self.notify_msg(subscriber_objs, msg)

    def subscribe_msg(self, subscriber_obj, publiser_obj):
        if publiser_obj not in self.publiser_objs_map:
            print('this publisher:%s not exit'% publiser_obj.publiser_name)
            return
        self.publiser_to_subscirber_map[publiser_obj].append(subscriber_obj)
    
    def notify_msg(self, subscriber_objs, msg):
        for subscriber_obj in subscriber_objs:
            subscriber_obj.receive_new_msg(msg)


PublisherManager = _PublisherManager()


class PubliserBase(object):

    def __init__(self, name):
        self.publiser_name = name

    def register_publiser(self):
        if not self.check_register_condition():
            print('sorry, register wrong')
            return
        PublisherManager.register_publiser(self)

    def publish_msg(self, msg):
        PublisherManager.publish_msg(self, msg)

    def check_register_condition(self):
        pass

class PubliserAndroid(PubliserBase):

    def __init__(self, name):
        super(PubliserAndroid, self).__init__(name)  
        self.system_version = 0

    def set_system_version(self, version_id):
        self.system_version = version_id
    
    def check_register_condition(self):
        if self.system_version >= 4.0:
            return True
        else:
            print('cur version:%f is too low'%self.system_version)
            return False

class PubliserIOS(PubliserBase):

    def __init__(self, name):
        super(PubliserIOS, self).__init__(name)  
        self.system_version = 0

    def set_system_version(self, version_id):
        self.system_version = version_id
    
    def check_register_condition(self):
        if self.system_version >= 8.0:
            return True
        else:
            return False



class SubscriberBase(object):
    def __init__(self, name):
        self.subscriber_name = name
    
    def subscribe_msg(self, publiser):
        PublisherManager.subscribe_msg(self, publiser)
        
    def receive_new_msg(self, msg):
        pass

class SubscriberAndroid(SubscriberBase):
    # 安卓平台注册的用户
    def receive_new_msg(self, msg):
        print('android platform user:%s reveive a new msg:%s'%(self.subscriber_name, msg))

class SubscriberIOS(SubscriberBase):
    # ios平台注册的用户
    def receive_new_msg(self, msg):
        print('ios platform user:%s reveive a new msg:%s'%(self.subscriber_name, msg))


if __name__ == "__main__":
    new_publiser = PubliserAndroid('PythonCommunity')
    new_publiser.set_system_version(6.0)
    new_publiser.register_publiser()

    user1 = SubscriberAndroid('xiaohong')
    user2 = SubscriberIOS('xiaoming')

    user1.subscribe_msg(new_publiser)
    user2.subscribe_msg(new_publiser)

    msg = {'tilte':'hello python'}
    new_publiser.publish_msg(msg)

• 这里简单的用不同的平台版本号作为是否可以注册发布者的条件。