設計模式之python版（十）–觀察者模式

觀察者模式：

情境特性：

結構特性：

#!/usr/bin/env python  #encoding: utf-8class subject:    def __init__(self):        self.obs = []        def add_ob(self, ob):        self.obs.append(ob)            def del_ob(self, ob):        self.obs.remove(ob)            def notify(self):        for ob in self.obs:            ob.update()class observer:    def __init__(self):        pass            def update(self):        pass        class create_subject(subject):    def __init__(self):        subject.__init__(self)        self.substatue = ''        class create_ob(observer):    def __init__(self, name, csubj):        self.name = name        self.status = ''        self.csubj = csubj            def update(self):        print '觀察者{%s}的新狀態是{%s}' % (self.name, self.csubj.substatue)    if '__main__' == __name__:     csub = create_subject()     csub.add_ob(create_ob('A', csub))     csub.add_ob(create_ob('B', csub))     csub.add_ob(create_ob('C', csub))      csub.substatue = 'something happen'        csub.notify()    

結果：

觀察者{A}的新狀態是{something happen}觀察者{B}的新狀態是{something happen}觀察者{C}的新狀態是{something happen}