代理模式
应用特性：需要在通信双方中间需要一些特殊的中间操作时引用，多加一个中间控制层。
结构特性：建立一个中间类，创建一个对象，接收一个对象，然后把两者联通起来
UML：
#!/usr/bin/env python
#encoding: utf-8
class sender_base:
def __init__(self):
pass
def send_something(self, something):
pass
class send_class(sender_base):
def __init__(self, receiver):
self.receiver = receiver
def send_something(self, something):
print "SEND " + something + ' TO ' + self.receiver.name
class agent_class(sender_base):
def __init__(self, receiver):
self.send_obj = send_class(receiver)
def send_something(self, something):
self.send_obj.send_something(something)
class receive_class:
def __init__(self, someone):
self.name = someone
if '__main__' == __name__:
receiver = receive_class('xiaohua')
agent = agent_class(receiver)
agent.send_something('agentinfo')
print receiver.__class__
print agent.__class__
结果：
SEND agentinfo TO xiaohua
__main__.receive_class
__main__.agent_class