python 多线程笔记（4）-- 车站售票模拟

import threading
import time
import random

class Worker(threading.Thread):
    '''售票员'''
    def __init__(self, wait_num=5, index=0):
        super().__init__()
        self.wait_num = wait_num          # 当前排队人数
        self.setName('窗口' + str(index)) # 窗口号
 
    def run(self):
        global counter, mutex
        
        while counter and self.wait_num: # 若有余票且有人排队
            # ============================
            # 窗口问询
            # ============================
            time.sleep(random.randrange(2,10)) # 比较耗时，时间随机
            
            # ============================
            # 出票
            # ============================
            mutex.acquire()         # 锁住①
            if counter == 0:        # 如果票数为0
                mutex.release()     # 解锁③ -----> 这句很重要！！！
                print(self.getName(), '：抱歉，票已售完')
                break
                
            counter = counter - 1   # 票数减一
            print('{}：当前余票 {} 张'.format(self.getName(), counter))
            mutex.release()         # 解锁③
            
            # ============================
            # 排队人数变化
            # ============================
            self.wait_num -= 1                      # 排队人数减一
            self.wait_num += random.randrange(0,2)  # 排队人数随机增加

    
if __name__ == '__main__':
    # 剩余车票数
    counter = 20
    
    # 创建锁
    mutex = threading.Lock()
    
    # 开4个售票窗口
    workers = []
    for i in range(4):
        wait_num = random.randrange(2,10) # 窗口前排队人数随机
        workers.append(Worker(wait_num, i+1)) 
    
    # 开始售票
    for w in workers:
        w.start()
    
    # 阻塞主程/后台静默？自己选
    #for w in workers:
    #    w.join()