第18章 多線程程式設計(5)

18.5.4 生産者-消費者問題和Queue子產品

from random import randint
from time import sleep
from Queue import Queue
from MyThread import MyThread

def writeQ(queue):
    print 'producting object for Q...'
    queue.put('xxx', 1)
    print 'size now: ', queue.qsize()
    
def readQ(queue):
    val = queue.get(1)
    print 'consumed object from Q... size now: ', queue.qsize()
    
def writer(queue, loops):
    for i in range(loops):
        writeQ(queue)
        sleep(randint(1, 3))

def reader(queue, loops):
    for i in range(loops):
        readQ(queue)
        sleep(randint(2, 5))

funcs = [writer, reader]
nfuncs = range(len(funcs))

nloops = randint(2, 5)
q = Queue(32)

threads = []
for i in nfuncs:
    t = MyThread(funcs[i], (q, nloops), funcs[i].__name__)
    threads.append(t)

for i in nfuncs:
    threads[i].start()
    
for i in nfuncs:
    threads[i].join()

print 'ALL DONE...'
           

Queue子產品可以用來進行線程間通訊，讓各個線程之間共享資料。

由于Python解釋器是單線程的，是以不是所有的程式都能從多線程中得到好處。