#!/usr/bin/env python
# -*- coding:utf-8 -*-
__author__ = 'Andy'
"""
大話設(shè)計(jì)模式
設(shè)計(jì)模式——觀察者模式
觀察者模式又叫做發(fā)布-訂閱模式 (Publish Subscribe Pattern):定義了一種一對多的關(guān)系，讓多個(gè)觀察對象同時(shí)監(jiān)聽一個(gè)主題對象，當(dāng)主題對象狀態(tài)發(fā)生變化時(shí)會通知所有觀察者,是它們能夠自動更新自己
使用場景:當(dāng)一個(gè)對象的改變需要同時(shí)改變其他對象的時(shí)候,而且它不知道具體有多少對象待改變
"""
#抽象通知者類
class Subject(object):
  def attach(self, observer):
    pass
  def detach(self,observer):
    pass
  def notify(self):
    pass
#具體通知者類
class Boss(Subject):
  def __init__(self):
    self.observer_list = []
    self.subject_status = ''
  def attach(self, observer):
    self.observer_list.append(observer)
  def detach(self,observer):
    self.observer_list.remove(observer)
  def notify(self):
    for item in self.observer_list:
      item.update()
#抽象觀察者類
class Observer(object):
  def __init__(self, name, publish):
    self.name = name
    self.publish = publish
  def update(self):
    pass
#具體觀察者類-看股票的人
class StockObserver(Observer):
  def update(self):
    print self.publish.subject_status,self.name,'關(guān)閉股票行情,繼續(xù)工作'
#具體觀察者類-看NBA的人
class NbaObserver(Observer):
  def update(self):
    print self.publish.subject_status,self.name,'關(guān)閉NBA,繼續(xù)工作'
if __name__ == "__main__":
  publisher = Boss()
  stocker = StockObserver('Andy',publisher)
  nbaer = NbaObserver('Tracy',publisher)
  publisher.attach(stocker)
  publisher.attach(nbaer)
  publisher.subject_status = '本老板回來了'
  publisher.notify()