如何在 Python 中使用观察者模式解决问题

from pydispatch import dispatcher

# 定义事件名称
EVENT_NAME = 'pidancode.com_updated'

class PidanCode:
    def __init__(self, name):
        self.name = name
        self.data = None

    def update_data(self, data):
        self.data = data
        # 发送事件通知观察者
        dispatcher.send(event=EVENT_NAME, sender=self)

class Observer:
    def __init__(self, name):
        self.name = name
        # 注册事件监听器
        dispatcher.connect(self.handle_event, signal=EVENT_NAME, sender=dispatcher.Any)

    def handle_event(self, sender):
        # 处理事件
        if isinstance(sender, PidanCode):
            print(f'{self.name} received update from {sender.name}: {sender.data}')

# 创建一个被观察者对象
pidancode = PidanCode('pidancode.com')

# 创建两个观察者对象
observer1 = Observer('Observer 1')
observer2 = Observer('Observer 2')

# 更新被观察者对象的数据，并自动通知观察者
pidancode.update_data('New data')

# 输出：
# Observer 1 received update from pidancode.com: New data
# Observer 2 received update from pidancode.com: New data