Module infinibatch.closablequeue

Classes

class ClosedException (...)

Common base class for all non-exit exceptions.

Expand source code

class ClosedException(Exception):
    pass

Ancestors

• builtins.Exception
• builtins.BaseException

class ClosableQueue (maxsize: int = 1000)

A thread-safe queue that can be closed

As long as the the queue is not closed, it behaves just like a thread-safe queue with a capacity limit: - put blocks until the item can be added - get blocks until there is an item to be returned

Once the queue is closed, no more items can be added but existing items can be removed: - put always raises a ClosedException - get returns an item if the queue is not empty and otherwise raises a ClosedException

Expand source code

class ClosableQueue:
    """
    A thread-safe queue that can be closed

    As long as the the queue is not closed, it behaves just like a thread-safe queue with a capacity limit:
        - put blocks until the item can be added
        - get blocks until there is an item to be returned

    Once the queue is closed, no more items can be added but existing items can be removed:
        - put always raises a ClosedException
        - get returns an item if the queue is not empty and otherwise raises a ClosedException
    """
    def __init__(self, maxsize: int=1000):
        self._maxsize = maxsize
        self._queue = deque()
        self._mutex = Lock()
        self._not_empty = Condition(self._mutex)
        self._not_full = Condition(self._mutex)
        self._closed = False

    def put(self, item):
        with self._not_full:
            if self._closed:
                raise ClosedException('This queue has been closed, no more items can be added.')
            while len(self._queue) >= self._maxsize:
                self._not_full.wait()
                if self._closed:
                    raise ClosedException('This queue has been closed, no more items can be added.')
            self._queue.append(item)
            self._not_empty.notify()
        
    def get(self):
        with self._not_empty:
            if self._closed and len(self._queue) == 0:
                raise ClosedException('This queue has been closed and is empty, no more items can be retrieved.')
            while len(self._queue) == 0:
                self._not_empty.wait()
                if self._closed and len(self._queue) == 0:
                    raise ClosedException('This queue has been closed and is empty, no more items can be retrieved.')
            item = self._queue.popleft()
            self._not_full.notify()
        return item
            
    def close(self):
        with self._mutex:
            self._closed = True
            self._not_empty.notify_all()
            self._not_full.notify_all()

Methods

def put(self, item)

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def put(self, item):
    with self._not_full:
        if self._closed:
            raise ClosedException('This queue has been closed, no more items can be added.')
        while len(self._queue) >= self._maxsize:
            self._not_full.wait()
            if self._closed:
                raise ClosedException('This queue has been closed, no more items can be added.')
        self._queue.append(item)
        self._not_empty.notify()

def get(self)

Expand source code

def get(self):
    with self._not_empty:
        if self._closed and len(self._queue) == 0:
            raise ClosedException('This queue has been closed and is empty, no more items can be retrieved.')
        while len(self._queue) == 0:
            self._not_empty.wait()
            if self._closed and len(self._queue) == 0:
                raise ClosedException('This queue has been closed and is empty, no more items can be retrieved.')
        item = self._queue.popleft()
        self._not_full.notify()
    return item

def close(self)

Expand source code

def close(self):
    with self._mutex:
        self._closed = True
        self._not_empty.notify_all()
        self._not_full.notify_all()