【吴师傅的Python面包店】Day 5

"""每位师傅做的面包上面都有师傅的标示，这样吴师傅就能哪位师傅的面包更受欢迎了。"""

import time
import threading
import random

TOTAL = []
END_FLAG = False
PRODUCER_NUM = 3

def producer(lock, p_num):
    """生产面包。"""
    producer_flag = 'P:%s' % p_num
    num = 0
    global TOTAL
    while True:
        time.sleep(1)
        lock.acquire()
        TOTAL.append(producer_flag)
        lock.release()
        print('Producer: I produced one.')
        num += 1
        if num >= 3:
            # 师傅做3个面包就要下班了。
            print('Done.')
            break

def consumer(lock):
    """消费者，买到面包总要说点什么吧。"""
    global TOTAL
    global END_FLAG
    while not END_FLAG:
        if TOTAL:
            lock.acquire()
            producer_flag = TOTAL.pop()
            print('Consumer: The flag is %s' % producer_flag)
            choice_flag = random.choice(['P:0', 'P:1', 'P:2'])
            if producer_flag != choice_flag:
                print('Consumer: I don\'t want:', producer_flag)
                TOTAL.append(producer_flag)
            lock.release()
        else:
            time.sleep(2)
            print("Consumer: I am waiting!")
    print("Consumer: Oh no!")

def run():
    lock = threading.Lock()
    producers = []
    for i in range(PRODUCER_NUM):
        p = threading.Thread(target=producer, args=(lock, i,))
        producers.append(p)
        p.start()
    c = threading.Thread(target=consumer, args=(lock,))
    c.start()
    for p in producers:
        p.join()
    global END_FLAG
    global TOTAL
    while TOTAL:
        # 得等面包卖完才能关门呢。
        time.sleep(1)
    END_FLAG = True    # 关门了，顾客消费也要停止
    c.join()

if __name__ == "__main__":
    run()