找到一本PYTHON并发编辑的书，
弄弄。。
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import threading
import time
shared_resource_with_lock = 0
shared_resource_with_no_lock = 0
COUNT = 100000
shared_resource_lock = threading.Lock()
class Box(object):
lock = threading.RLock()
def __init__(self):
self.total_items = 0
def execute(self, n):
Box.lock.acquire()
self.total_items += n
Box.lock.release()
def add(self):
Box.lock.acquire()
self.execute(1)
Box.lock.release()
def remove(self):
Box.lock.acquire()
self.execute(-1)
Box.lock.release()
def adder(box, items):
while items > 0:
print("adding 1 item in the box\n")
box.add()
time.sleep(5)
items -= 1
def remover(box, items):
while items > 0:
print("removing 1 item in the box")
box.remove()
time.sleep(5)
items -= 1
def increment_with_lock():
global shared_resource_with_lock
for i in range(COUNT):
shared_resource_lock.acquire()
shared_resource_with_lock += 1
shared_resource_lock.release()
def decrement_with_lock():
global shared_resource_with_lock
for i in range(COUNT):
shared_resource_lock.acquire()
shared_resource_with_lock -= 1
shared_resource_lock.release()
def increment_without_lock():
global shared_resource_with_no_lock
for i in range(COUNT):
shared_resource_with_no_lock += 1
def decrement_without_lock():
global shared_resource_with_no_lock
for i in range(COUNT):
shared_resource_with_no_lock -= 1
if __name__ == "__main__":
t1 = threading.Thread(target = increment_with_lock)
t2 = threading.Thread(target = decrement_with_lock)
t3 = threading.Thread(target = increment_without_lock)
t4 = threading.Thread(target = decrement_without_lock)
t1.start()
t2.start()
t3.start()
t4.start()
t1.join()
t2.join()
t3.join()
t4.join()
print ("the value of shared variable with lock management is %s"\
%shared_resource_with_lock)
print ("the value of shared variable with race condition is %s"\
%shared_resource_with_no_lock)
items = 5
print("putting %s items in the box " % items)
box = Box()
t1 = threading.Thread(target=adder, args=(box, items))
t2 = threading.Thread(target=remover, args=(box, items))
t1.start()
t2.start()
t1.join()
t2.join()
print ("%s items still remain in the box " % box.total_items)
