class documentation

class twisted.internet.defer.DeferredQueue: (source)

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An event driven queue.

Objects may be added as usual to this queue. When an attempt is made to retrieve an object when the queue is empty, a Deferred is returned which will fire when an object becomes available.

Instance Variable size The maximum number of objects to allow into the queue at a time. When an attempt to add a new object would exceed this limit, QueueOverflow is raised synchronously. None for no limit.
Instance Variable backlog The maximum number of Deferred gets to allow at one time. When an attempt is made to get an object which would exceed this limit, QueueUnderflow is raised synchronously. None for no limit.
Method __init__ Undocumented
Instance Variable waiting Undocumented
Instance Variable pending Undocumented
Method put Add an object to this queue.
Method get Attempt to retrieve and remove an object from the queue.
Method _cancelGet Remove a deferred d from our waiting list, as the deferred has been canceled.
size = (source)
The maximum number of objects to allow into the queue at a time. When an attempt to add a new object would exceed this limit, QueueOverflow is raised synchronously. None for no limit.
backlog = (source)
The maximum number of Deferred gets to allow at one time. When an attempt is made to get an object which would exceed this limit, QueueUnderflow is raised synchronously. None for no limit.
def __init__(self, size=None, backlog=None): (source)

Undocumented

waiting = (source)

Undocumented

(type: list)
pending = (source)

Undocumented

(type: list)
def _cancelGet(self, d): (source)

Remove a deferred d from our waiting list, as the deferred has been canceled.

Note: We do not need to wrap this in a try/except to catch d not being in self.waiting because this canceller will not be called if d has fired. put() pops a deferred out of self.waiting and calls it, so the canceller will no longer be called.

ParametersdThe deferred that has been canceled.
def put(self, obj): (source)

Add an object to this queue.

RaisesQueueOverflowToo many objects are in this queue.
def get(self): (source)

Attempt to retrieve and remove an object from the queue.

Returnsa Deferred which fires with the next object available in the queue.
RaisesQueueUnderflowToo many (more than backlog) Deferreds are already waiting for an object from this queue.
API Documentation for Twisted, generated by pydoctor 20.12.1 at 2021-02-28 19:53:36.