python使用threading.condition实现生产者消费者

threading模块

threading.Condition() ，返回condition对象，相当于高级锁对象，可以使一个或多个线程等待直到被其他线程调度或通知

condition条件对象提供如下方法：

1.threading.Condition()

2.acquire(*args) 获取锁

3.release()释放锁

4.wait([timeout]) 等待

5.notify(n=1) / notifyAll() 唤醒

生产者与消费者问题

ps：queue也可实现生产者消费者，<<详情参考>>

#生产者
# Consume one item
cv.acquire()
while not an_item_is_available():
cv.wait()
get_an_available_item()
cv.release()

#消费者
# Produce one item
cv.acquire()
make_an_item_available()
cv.notify()
cv.release()

示例：

描述：

一件产品。投放到市场上，市场需求可以看作一个箱子box，有一个容量限度

当小于box大小，生产者可以生产，否则等待消费者消费，生产者有生产效率，使用speed表示

当产品大于0，才可进行消费，否则就等待生产者生产

# encoding=utf8
import threading
import time
from decimal import Decimal

condition = threading.Condition()
num = 0
box_size=15

class GoodsProduce(threading.Thread):
def __init__(self,companyName,produceSpeed,info):
super(GoodsProduce,self).__init__()
self.companyName=companyName
self.produceSpeed=Decimal(2/produceSpeed).quantize(Decimal('0.00'))
self.info=info

def run(self):
global num
while True:
if condition.acquire():
if num < box_size:
time.sleep(self.produceSpeed)
num += 1;
print "GoodsProduce : %s create one , now box have :%d" %(self.companyName, num)
condition.notify()
condition.release()
else:
print "NOTE: BOX is full , size %d ,filled %d" %(box_size, num)
condition.wait();

def show(self):
print "companyName -- %s ,produceSpeed -- %s, infomation -- %s"%(self.companyName,self.produceSpeed,self.info)

class GoodsConsume(threading.Thread):
def __init__(self,cname,area,info):
super(GoodsConsume,self).__init__()
self.cname=cname
self.area=area
self.info=info

def run(self):
global num
while True:
if condition.acquire():
if num >= 1:
num -= 1
print "GoodsConsumer %s get one , now box have :%d" %(self.cname,num)
condition.notify()
condition.release()
else:
print "NOTE: BOX is null ,please wait ...  size %d ,fillin %d" % (box_size, num)
time.sleep(1)
condition.wait();
time.sleep(1)
def show(self):
print "GoodsConsume %s area -- %s ,infomation -- %s"%(self.cname,self.area,self.info)

if __name__ == "__main__":
for server_num in range(0, 2):
server = GoodsProduce("Prd-%d"%server_num,server_num+1,"this is %d prd company"%server_num)
server.start()
server.show()

for customer_num in range(0, 5):
customer = GoodsConsume("cus-%d"%customer_num,"area-%d"%customer_num,"this is %d customer"%customer_num)
customer.start()
customer.show()

结果：

companyName -- Prd-0 ,produceSpeed -- 2.00, infomation -- this is 0 prd company
companyName -- Prd-1 ,produceSpeed -- 1.00, infomation -- this is 1 prd company
GoodsConsume cus-0 area -- area-0 ,infomation -- this is 0 customer
GoodsConsume cus-1 area -- area-1 ,infomation -- this is 1 customer
GoodsConsume cus-2 area -- area-2 ,infomation -- this is 2 customer
GoodsConsume cus-3 area -- area-3 ,infomation -- this is 3 customer
GoodsConsume cus-4 area -- area-4 ,infomation -- this is 4 customer
GoodsProduce : Prd-0
4000
create one , now box have :1
GoodsProduce : Prd-0 create one , now box have :2
GoodsProduce : Prd-0 create one , now box have :15
NOTE: BOX is full , size 15 ,filled 15
GoodsConsumer cus-1 get one , now box have :14
GoodsConsumer cus-2 get one , now box have :13
GoodsConsumer cus-3 get one , now box have :12
GoodsConsumer cus-4 get one , now box have :11
GoodsProduce : Prd-1 create one , now box have :12
GoodsProduce : Prd-1 create one , now box have :13
GoodsProduce : Prd-1 create one , now box have :14
GoodsProduce : Prd-1 create one , now box have :15
NOTE: BOX is full , size 15 ,filled 15
GoodsConsumer cus-2 get one , now box have :14
GoodsConsumer cus-4 get one , now box have :13
GoodsConsumer cus-0 get one , now box have :12
GoodsProduce : Prd-0 create one , now box have :13
GoodsProduce : Prd-0 create one , now box have :14
GoodsProduce : Prd-0 create one , now box have :15
NOTE: BOX is full , size 15 ,filled 15
GoodsConsumer cus-1 get one , now box have :14
GoodsConsumer cus-3 get one , now box have :13
GoodsProduce : Prd-1 create one , now box have :14
GoodsProduce : Prd-1 create one , now box have :15
NOTE: BOX is full , size 15 ,filled 15