python对象池模式

class QueueObject():

    def __init__(self, queue, auto_get=False):
        self._queue = queue
        self.object = self._queue.get() if auto_get else None

    def __enter__(self):
        if self.object is None:
            self.object = self._queue.get()
        return self.object

    def __exit__(self, Type, value, traceback):
        if self.object is not None:
            self._queue.put(self.object)
            self.object = None

    def __del__(self):
        if self.object is not None:
            self._queue.put(self.object)
            self.object = None

def main():
    try:
        import queue
    except ImportError:  # python 2.x的兼容性
        import Queue as queue

    def test_object(queue):
        queue_object = QueueObject(queue, True)
        print('内部 func: {}'.format(queue_object.object))

    sample_queue = queue.Queue()
    sample_queue.put('yam')
    with QueueObject(sample_queue) as obj:
        print('Inside with: {}'.format(obj))
    print('Outside with: {}'.format(sample_queue.get()))

    sample_queue.put('sam')
    test_object(sample_queue)
    print('外部 func: {}'.format(sample_queue.get()))

    if not sample_queue.empty():
        print(sample_queue.get())

if __name__ == '__main__':
    main()