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('33[42;1m--green light on---33[0m')
        elif count <13:
            print('33[43;1m--yellow light on---33[0m')
        elif count <20:
            if event.isSet():
                event.clear()
            print('33[41;1m--red light on---33[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