twisted.internet.task.CooperativeTask

A CooperativeTask is a task object inside a Cooperator, which can be paused, resumed, and stopped. It can also have its completion (or termination) monitored.

See Also Cooperator.cooperate

Method	__init__	A private constructor: to create a new `CooperativeTask`, see `Cooperator.cooperate`.
Method	whenDone	Get a `defer.Deferred` notification of when this task is complete.
Method	pause	No summary
Method	resume	Resume processing of a paused `CooperativeTask`.
Method	stop	Stop further processing of this task.
Instance Variable	_iterator	the iterator to iterate when this `CooperativeTask` is asked to do work.
Instance Variable	_cooperator	the `Cooperator` that this `CooperativeTask` participates in, which is used to re-insert it upon resume. (type: `Cooperator`)
Instance Variable	_deferreds	the list of `defer.Deferred`s to fire when this task completes, fails, or finishes. (type: `list`)
Instance Variable	_pauseCount	the number of times that this `CooperativeTask` has been paused; if 0, it is running. (type: `int`)
Instance Variable	_completionState	The completion-state of this `CooperativeTask`. `None` if the task is not yet completed, an instance of `TaskStopped` if `stop` was called to stop this task early, of `TaskFailed` if the application code in the iterator raised an exception which caused it to terminate, and of `TaskDone` if it terminated normally via raising `StopIteration`. (type: `TaskFinished`)
Method	_completeWith
Method	_checkFinish	If this task has been stopped, raise the appropriate subclass of `TaskFinished`.
Method	_oneWorkUnit	Perform one unit of work for this task, retrieving one item from its iterator, stopping if there are no further items in the iterator, and pausing if the result was a `defer.Deferred`.

_iterator =

the iterator to iterate when this CooperativeTask is asked to do work.

_cooperator =

the Cooperator that this CooperativeTask participates in, which is used to re-insert it upon resume. (type: Cooperator)

_deferreds =

the list of defer.Deferreds to fire when this task completes, fails, or finishes. (type: list)

_pauseCount =

the number of times that this CooperativeTask has been paused; if 0, it is running. (type: int)

_completionState =

The completion-state of this CooperativeTask. None if the task is not yet completed, an instance of TaskStopped if stop was called to stop this task early, of TaskFailed if the application code in the iterator raised an exception which caused it to terminate, and of TaskDone if it terminated normally via raising StopIteration. (type: TaskFinished)

def __init__(self, iterator, cooperator):

A private constructor: to create a new CooperativeTask, see Cooperator.cooperate.

def whenDone(self):

Get a defer.Deferred notification of when this task is complete.

Returns a defer.Deferred that fires with the iterator that this CooperativeTask was created with when the iterator has been exhausted (i.e. its next method has raised StopIteration), or fails with the exception raised by next if it raises some other exception. (type: defer.Deferred)

def pause(self):

Pause this CooperativeTask. Stop doing work until CooperativeTask.resume is called. If pause is called more than once, resume must be called an equal number of times to resume this task.

Raises TaskFinished if this task has already finished or completed.

def resume(self):

Resume processing of a paused CooperativeTask.

Raises NotPaused if this CooperativeTask is not paused.

def _completeWith(self, completionState, deferredResult):

Parameters	completionState	a `TaskFinished` exception or a subclass thereof, indicating what exception should be raised when subsequent operations are performed.
	deferredResult	the result to fire all the deferreds with.

def stop(self):

Stop further processing of this task.

Raises TaskFinished if this CooperativeTask has previously completed, via stop, completion, or failure.

def _checkFinish(self):

If this task has been stopped, raise the appropriate subclass of TaskFinished.

def _oneWorkUnit(self):

Perform one unit of work for this task, retrieving one item from its iterator, stopping if there are no further items in the iterator, and pausing if the result was a defer.Deferred.

API Documentation for twisted, generated by pydoctor at 2020-03-25 17:34:30.

twisted.internet.task.CooperativeTask(object) class documentation

`twisted.internet.task.CooperativeTask(object)` class documentation