python线程之condition

import threading,time

cond = threading.Condition()
#cond.acquire()
#cond.release()
#cond.wait()
#cond.notify()
def aa():
    print (‘thread_aa get‘)
    cond.acquire()
    time.sleep(5)
    print (‘thread_aa finished first job‘)
    cond.wait()#释放对锁的控制，好让别的进程acquire到
               #同时阻塞在此，等待得到锁的那个进程的先cond.notify后(cond.wait或cond.release)
    print (‘thread_aa get again‘)
    time.sleep(5)
    print (‘thread_aa finished all work‘)
    cond.notify()#告诉刚才释放锁的那个进程等通知吧,等我要么wait要么release
    cond.release()#释放锁
def bb():
    cond.acquire()
    print (‘thread_bb get‘)
    cond.notify()#告诉刚才释放锁的那个进程等通知吧,等我要么wait要么release
    print (‘依然是我bb在运行‘)
    time.sleep(5)
    print (‘thread_bb finished first job‘)
    cond.wait()#释放对锁的控制，而后被阻塞的aa就可以执行了
            #同时阻塞在此，等待得到锁的aa的先cond.notify后(cond.wait或cond.release)
    print (‘thread_aa get again‘)    
    print (‘thread_bb finished all works‘)
    cond.release()
    
a=threading.Thread(target=aa)
a.start()
time.sleep(2)
b=threading.Thread(target=bb)
b.start()