【吴师傅的Python面包店】Day 4

"""吴师傅请多了两个python面包师傅，工作似乎轻松了很多。"""

import time
import threading

TOTAL = 0
END_FLAG = False
PRODUCER_NUM = 3

def producer(lock):
    """生产面包。"""
    num = 0
    global TOTAL
    while True:
        time.sleep(1)
        lock.acquire()
        TOTAL += 1
        lock.release()
        print('Producer: I produced one.')
        num += 1
        if num >= 3:
            # 现在师傅做3个面包就可以下班了。
            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 > 0:
            print("Consumer: I am so happy.")
            lock.acquire()
            TOTAL -= 1
            lock.release()
        else:
            time.sleep(2)
            print("Consumer: I am waiting!")
    print("Consumer: Oh no!")

def run():
    lock = threading.Lock()
    producers = []
    for _ in range(PRODUCER_NUM):
        p = threading.Thread(target=producer, args=(lock,))
        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()