【发布时间】：2018-03-29 17:07:23
【问题描述】：
问题：
男女均可使用男女通用的浴室。
卫生间容量无限，但男女不能同时使用卫生间。
我在执行性别隔离条款时遇到了麻烦。我正在尝试使用“信号量小书”中的 LightSwitch 设计模式，但我无法弄清楚为什么当男性或女性在浴室时该模式不排除异性。
这不是作业问题。这是我在一次采访中轰炸的问题。
Users.py：
class User(object):
def __init__(self, cv, sex, line_full_event):
self.cv = cv
self.sex = sex
self.line_full_event = line_full_event
def enter_bathroom(self, bathroom):
with self.cv:
bathroom.enter(self.sex, self.cv)
def leave_bathroom(self, bathroom):
bathroom.leave(self.sex, self.cv)
class Male(User):
def __init__(self, cv, sex, line_full_event):
super(Male, self).__init__(cv, sex, line_full_event)
def go(self, bathroom):
logging.debug("Male queueing up")
self.line_full_event.wait()
super(Male, self).enter_bathroom(bathroom)
super(Male, self).leave_bathroom(bathroom)
class Female(User):
def __init__(self, cv, sex, line_full_event):
super(Female, self).__init__(cv, sex, line_full_event)
def go(self, bathroom):
logging.debug("Female queueing up")
self.line_full_event.wait()
super(Female, self).enter_bathroom(bathroom)
super(Female, self).leave_bathroom(bathroom)
LightSwitch.py：
class LightSwitch:
def __init__(self):
self.mutex = Lock()
self.count = 0
def inc(self, cv):
with self.mutex:
self.count += 1
logging.debug("inc-ing! count == %d", self.count)
if self.count == 1:
cv.acquire()
def dec(self, cv):
with self.mutex:
self.count -= 1
logging.debug("dec-ing! count == %d", self.count)
if self.count == 0:
cv.notify_all()
cv.release()
浴室.py
MALE = 1
FEMALE = 0
class Bathroom:
def __init__(self):
self.male_switch = LightSwitch()
self.female_switch = LightSwitch()
def enter(self, sex, cv):
if sex == MALE:
self.female_switch.inc(cv)
elif sex == FEMALE:
self.male_switch.inc(cv)
def leave(self, sex, cv):
if sex == MALE:
self.female_switch.dec(cv)
elif sex == FEMALE:
self.male_switch.dec(cv)
Main.py：
def Main():
logging.basicConfig(format='%(threadName)s, %(asctime)s, %(message)s', datefmt='%M:%S', level=logging.DEBUG)
# create Bathroom
b = Bathroom()
# create whatever threading objects we need
males_can_enter, females_can_enter = get_cvs()
line_full = threading.Event()
for i in range(10):
if random.randint(0,1) == MALE:
# create Male user
user = Male(males_can_enter, MALE, line_full)
else:
# create Female user
user = Female(females_can_enter, FEMALE, line_full)
t = threading.Thread(target=user.go, args=(b,))
t.start()
logging.debug("we're off to the races!")
line_full.set()
def get_cvs():
return (threading.Condition(), threading.Condition())
if __name__ == '__main__':
Main()
输出：
Thread-1, 10:21, Male queueing up
Thread-2, 10:21, Female queueing up
Thread-3, 10:21, Male queueing up
Thread-4, 10:21, Female queueing up
Thread-5, 10:21, Male queueing up
Thread-6, 10:21, Female queueing up
Thread-7, 10:21, Male queueing up
Thread-8, 10:21, Female queueing up
Thread-9, 10:21, Female queueing up
Thread-10, 10:21, Male queueing up
MainThread, 10:21, we're off to the races!
Thread-2, 10:21, inc-ing! count == 1
Thread-3, 10:21, inc-ing! count == 1
Thread-3, 10:21, dec-ing! count == 0
Thread-2, 10:21, dec-ing! count == 0
Thread-5, 10:21, inc-ing! count == 1
Thread-9, 10:21, inc-ing! count == 1
Thread-5, 10:21, dec-ing! count == 0
Thread-9, 10:21, dec-ing! count == 0
Thread-4, 10:21, inc-ing! count == 1
Thread-7, 10:21, inc-ing! count == 1
Thread-4, 10:21, dec-ing! count == 0
Thread-7, 10:21, dec-ing! count == 0
Thread-8, 10:21, inc-ing! count == 1
Thread-10, 10:21, inc-ing! count == 1
Thread-8, 10:21, dec-ing! count == 0
Thread-10, 10:21, dec-ing! count == 0
Thread-1, 10:21, inc-ing! count == 1
Thread-6, 10:21, inc-ing! count == 1
Thread-1, 10:21, dec-ing! count == 0
Thread-6, 10:21, dec-ing! count == 0
【问题讨论】：
标签： python multithreading design-patterns