for ob in observers:
ob.update()
就可以看成多个观察者产生响应。
当然，这种实现并不好——被观察者也应该是一个实例。
更加完善的观察者模式实现
class ObserverInterface(object):
def __init__(self):
pass
def update(self):
pass
class SubjectInterface(object):
def __init__(self):
self.observers = set()
def addObserver(self, ob):
self.observers.add(ob)
def delObserver(self, ob):
self.observers.remove(ob)
def notifyObservers(self):
for ob in self.observers:
ob.update()
class Observer01(ObserverInterface):
def __init__(self, s):
self.s = s
def update(self):
print self.s
class Observer02(ObserverInterface):
def __init__(self, num1, num2):
self.num1 = num1
self.num2 = num2
def update(self):
print self.num1 + self.num2
class Subject01(SubjectInterface):
def __init__(self):
SubjectInterface.__init__(self)
if __name__ == '__main__':
ob01 = Observer01("hi, i am ob01")
ob02 = Observer02("hello,","i am ob02")
observers = set()
sb01 = Subject01()
sb01.addObserver(ob01)
sb01.addObserver(ob02)
sb01.notifyObservers()
运行结果如下：
hi, i am ob01
hello,i am ob02
