实现线程安全的队列Queue（Python）

忘是亡心i 2021-10-01 05:46 308阅读 0赞

### 关于队列 ###

用于存放多个元素，是存放各种元素的“池”。

###    实现的基本功能 ###

获取当前队列元素数量-->往队列放入元素-->往队列取出元素。

### 注意 ###

队列可能有多个线程同时操作，因此需要保证线程安全，如下两种情况：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h1YW5nbGVpMzA1_size_16_color_FFFFFF_t_70][]

### 具体实现 ###

# -*- encoding=utf-8 -*-
    
    
    import time
    import threading
    
    
    class ThreadSafeQueueException(Exception):
        pass
    
    
    # 线程安全的队列
    class ThreadSafeQueue(object):
    
        def __init__(self, max_size=0):
            self.queue = []
            self.max_size = max_size
            self.lock = threading.Lock()
            self.condition = threading.Condition()
    
        # 当前队列元素的数量
        def size(self):
            self.lock.acquire()
            size = len(self.queue)
            self.lock.release()
            return size
    
        # 往队列里面放入元素
        def put(self, item):
            if self.max_size != 0 and self.size() > self.max_size:
                return ThreadSafeQueueException()
            self.lock.acquire()
            self.queue.append(item)
            self.lock.release()
            self.condition.acquire()
            self.condition.notify()
            self.condition.release()
            pass
    
        def batch_put(self, item_list):
            if not isinstance(item_list, list):
                item_list = list(item_list)
            for item in item_list:
                self.put(item)
    
        # 从队列取出元素
        def pop(self, block=True, timeout=None):
            if self.size() == 0:
                # 需要阻塞等待
                if block:
                    self.condition.acquire()
                    self.condition.wait(timeout=timeout)
                    self.condition.release()
                else:
                    return None
            self.lock.acquire()
            item = None
            if len(self.queue) > 0:
                item = self.queue.pop()
            self.lock.release()
            return item
    
        def get(self, index):
            self.lock.acquire()
            item = self.queue[index]
            self.lock.release()
            return item
    
    
    if __name__ == '__main__':
        queue = ThreadSafeQueue(max_size=100)
    
        def producer():
            while True:
                queue.put(1)
                time.sleep(3)
    
        def consumer():
            while True:
                item = queue.pop(block=True, timeout=-1)
                print('get item from queue: %d' % item)
                time.sleep(1)
    
        thread1 = threading.Thread(target=producer)
        thread2 = threading.Thread(target=consumer)
        thread1.start()
        thread2.start()
        thread1.join()
        thread2.join()

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h1YW5nbGVpMzA1_size_16_color_FFFFFF_t_70]: /images/20210923/c5e06389210f49a3b72097a723e72db3.png