使用Condition对象可以在某些事件触发后才处理数据或执行特定的功能代码，可以用于不同线程之间的通信或通知，以实现更高级别的同步。在内部实现上，Condition对象总是与某种锁对象相关联。 Condition对象除了具有acquire()和release()方法之外，还有wait()、wait_for()、notify()、notify_all()等方法：
本文代码模拟了经典的生产者-消费者问题，使用列表模拟物品池，生产者往里放物品，消费者从中获取物品，物品池满时生产者等待，空时消费者等待。 import threading from random import randint from time import sleep #自定义生产者线程类 class Producer(threading.Thread): def __init__(self, threadname): threading.Thread.__init__(self,name=threadname)
def run(self): global x
while True: sleep(1) #获取锁 con.acquire() #假设共享列表中最多能容纳5个元素 if len(x) == 5: #如果共享列表已满，生产者等待 print('Producer is waiting.....') con.wait() else: r = randint(1, 1000) print('Produced:', r) #产生新元素，添加至共享列表 x.append(r) #唤醒等待条件的线程 con.notify()
#释放锁 con.release() #自定义消费者线程类 class Consumer(threading.Thread): def __init__(self, threadname): threading.Thread.__init__(self, name =threadname)
def run(self): global x
while True: sleep(2) #获取锁 con.acquire() if not x: #等待 print('Consumer is waiting.....') con.wait() else: print('Consumed:', x.pop(0)) con.notify()
con.release()
#创建Condition对象以及生产者线程和消费者线程 con = threading.Condition() x = [] Producer('Producer').start() Consumer('Consumer').start() 某次运行部分结果如下： Produced: 696 Produced: 970 Consumed: 696 Produced: 546 Produced: 30 Consumed: 970 Produced: 824 Produced: 68 Consumed: 546 Produced: 409 Produced: 172 Consumed: 30 Produced: 820 Producer is waiting..... Consumed: 824 Produced: 2 Producer is waiting..... Consumed: 68 Produced: 473 Producer is waiting..... Consumed: 409 Produced: 167 Consumed: 172 Produced: 192 Producer is waiting..... Consumed: 820 Produced: 789 Consumed: 2 Produced: 855 Producer is waiting..... Consumed: 473 Produced: 754 Producer is waiting..... Consumed: 167 Produced: 549 Consumed: 192 Produced: 100 Producer is waiting..... Consumed: 789 Produced: 862 Consumed: 855 Produced: 537 Producer is waiting..... Consumed: 754 Produced: 715 Consumed: 549 Produced: 79 Producer is waiting..... Consumed: 100 Produced: 445 Consumed: 862 Produced: 64 Producer is waiting..... Consumed: 537 Produced: 755 Consumed: 715 Produced: 8 ^C（按Crtl Break退出） |
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