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最近看设计模式,其中谈及到观察者模式.
可以理解为被观察者对外提供注册机制，观察者可以通过插入和移除实现订阅和取消订阅消息的功能，无论观察者有没有注册, 都不会影响被观察者发布消息.
而这在mmdetection中体现的很好.
举个例子来观察每天我的生活:
其中register_hook用来注册HOOK来判断是否要观察我的每天生活.
import sys
class HOOK:
def before_getup(self, runner):
print('{}:赖床30分钟'.format(sys._getframe().f_code.co_name))
print('==runner:', runner)
def after_getup(self, runner):
print('{}:刷牙洗脸'.format(sys._getframe().f_code.co_name))
print('==runner:', runner)
def before_lunch(self, runner):
print('{}:吃午饭之前上厕所'.format(sys._getframe().f_code.co_name))
print('==runner:', runner)
def after_lunch(self, runner):
print('{}:吃完午饭午休30分钟'.format(sys._getframe().f_code.co_name))
print('==runner:', runner)
def before_dinner(self, runner):
print('{}: 摸鱼30分钟'.format(sys._getframe().f_code.co_name))
print('==runner:', runner)
def after_dinner(self, runner):
print('{}: 回家睡觉'.format(sys._getframe().f_code.co_name))
print('==runner:', runner)
def after_finish_work(self, runner, are_you_busy=False):
if are_you_busy:
print('{}:今天事贼多，还是加班吧'.format(sys._getframe().f_code.co_name))
else:
print('{}:今天没啥事，看部电影'.format(sys._getframe().f_code.co_name))
print('==runner:', runner)
class Runner(object):
def __init__(self, ):
pass
self._hooks = []
def register_hook(self, hook):
# 这里不做优先级判断，直接在头部插入HOOK
self._hooks.insert(0, hook)
def call_hook(self, hook_name):
for hook in self._hooks:
getattr(hook, hook_name)(self)
def run(self):
print('开始启动我的一天')
self.call_hook('before_getup')
self.call_hook('after_getup')
self.call_hook('before_lunch')
self.call_hook('after_lunch')
self.call_hook('before_dinner')
self.call_hook('after_dinner')
self.call_hook('after_finish_work')
print('睡觉算求')
runner = Runner()
hook = HOOK()
runner.register_hook(hook)
runner.run()
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