040同步条件event

条件同步和条件变量同步差不多意思，只是少了锁功能，因为条件同步设计于不访问共享资源的条件环境，event=threading.Event():条件环境对象，初始值为False.
event.isSet():  返回event的状态值
event.wait():  如果event.isSet()==False将阻塞线程
event.set():  设置event的状态值为True，所有阻塞池的线程激活进入就绪状态，等待操作系统调度
event.clear():  恢复event的状态值为False

 import time,threading

 class Boss(threading.Thread):
     def run(self):
         print('Boss:今晚加班到22：00')
         event.isSet()or event.set()
         time.sleep(5)
         print('Boss:<22:00>可以下班了')
         event.isSet()orevent.set()

 class Worker(threading.Thread):
     def run(self):
         event.wait()
         print('Worker:命苦啊～')
         time.sleep(0.25)
         event.clear()
         event.wait()
         print('Worker:oh,yeah')

 if __name__ == '__main__':
     event = threading.Event()
     threads = []
     for i in range(5):
         threads.append(Worker())
     threads.append(Boss())
     for t in threads:
         t.start()
     for t in threads:
         t.join()

 import threading,time
 import random
 def light():
     if not event.isSet():
         event.set() #wait就不阻塞 #绿灯状态
     count = 0
     while True:
         if count < 10:
             print('\033[42;1m--green light on---\033[0m')
         elif count <13:
             print('\033[43;1m--yellow light on---\033[0m')
         elif count <20:
             if event.isSet():
                 event.clear()
             print('\033[41;1m--red light on---\033[0m')
         else:
             count = 0
             event.set() #打开绿灯
         time.sleep(1)
         count +=1
 def car(n):
     while 1:
         time.sleep(random.randrange(10))
         if  event.isSet(): #绿灯
             print("car [%s] is running.." % n)
         else:
             print("car [%s] is waiting for the red light.." %n)
 if __name__ == '__main__':
     event = threading.Event()
     Light = threading.Thread(target=light)
     Light.start()
     for i in range(3):
         t = threading.Thread(target=car,args=(i,))
         t.start()

来自：http://www.cnblogs.com/yuanchenqi/articles/5733873.html