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"""Protocol definition.""" |
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import sys |
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from typing import Any, NoReturn, Optional, TypeVar, Union |
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# Protocol is only available in Python 3.8+. |
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if sys.version_info.minor > 7: # pragma: no cover |
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from typing import Protocol |
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else: # pragma: no cover |
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from typing_extensions import Protocol # type: ignore |
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__all__ = [ |
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"Subscription", |
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"NextHandler", |
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"CompleteHandler", |
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"ErrorHandler", |
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"Observable", |
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"Observer", |
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"Collector", |
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"Subscribe", |
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"Subject", |
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"ConnectHandler", |
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"RefCountHandler", |
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"ConnectableObservable", |
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"ObservableFactory", |
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"SubjectEventHandler", |
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"SubjectHandler", |
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"ConnectableObservableEventHandler", |
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"ConnectableObservableHandler", |
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"PredicateOperator", |
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"AccumulatorOperator", |
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"SubjectFactory", |
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] |
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T = TypeVar('T') |
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class Subscription(Protocol): |
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"""Subscription Protocol. |
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Subscription is a function to release resources or cancel Observable executions (act as a Disposable). |
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It define something to be used and thrown away after you call it. |
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""" |
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async def __call__(self) -> None: # pragma: no cover |
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"""Release subscription.""" |
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pass |
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class NextHandler(Protocol): |
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"""NextHandler Protocol. |
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A next handler process an item from associated observable. |
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""" |
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async def __call__(self, item: Any) -> None: # pragma: no cover |
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"""Process item.""" |
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pass |
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class CompleteHandler(Protocol): |
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"""CompleteHandler Protocol. |
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A complete handler is call when no more item will came from the associated observable. |
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""" |
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async def __call__(self) -> None: # pragma: no cover |
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"""Signal completion of this observable.""" |
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pass |
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class ErrorHandler(Protocol): |
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"""ErrorHandler Protocol. |
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An error handler receive a message or an exception and raise it. |
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""" |
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async def __call__(self, err: Any) -> Optional[NoReturn]: # pragma: no cover |
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"""Raise error. |
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Args: |
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err (Union[Any, Exception]): the error to raise |
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Raises: |
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(Exception): the exception |
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""" |
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pass |
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class Observer(Protocol): |
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"""Observer Protocol. |
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What is an Observer? |
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An Observer is a consumer of values delivered by an Observable. |
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Observers are simply a set of callbacks, one for each type of notification |
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delivered by the Observable: |
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- next, |
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- error, |
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- and complete. |
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Observers are just "objects" with three callbacks, one for each type of |
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notification that an Observable may deliver. |
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""" |
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async def on_next(self, item: Any) -> None: # pragma: no cover |
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"""Process item.""" |
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pass |
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async def on_completed(self) -> None: # pragma: no cover |
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"""Signal completion of this observable.""" |
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pass |
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async def on_error(self, err: Any) -> Optional[NoReturn]: # pragma: no cover |
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pass |
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class Collector(Observer, Protocol): |
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"""Collector Observer Protocol.""" |
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def result(self) -> Any: # pragma: no cover |
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"""Returns result.""" |
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pass |
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def is_finish(self) -> bool: # pragma: no cover |
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"""Return true if observable has completed.""" |
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pass |
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def has_error(self) -> bool: # pragma: no cover |
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"""Return true if observable has meet error.""" |
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pass |
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def error(self) -> Any: # pragma: no cover |
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"""Return error if observable has meet error.""" |
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pass |
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class Subscribe(Protocol): |
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"""Subscribe Protocol. |
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It's a (sync/async) function wich take an observer and return a subscription. |
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""" |
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async def __call__(self, an_observer: Observer) -> Subscription: # pragma: no cover |
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"""Implement observer subscription. |
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Args: |
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observer (Observer): the observer instance |
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Returns: |
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(Subscription): subscription |
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""" |
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pass |
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class Observable(Protocol): |
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"""Observable Protocol. |
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An observable is something on which we can subscribe to listen event. |
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""" |
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async def subscribe(self, an_observer: Observer) -> Subscription: # pragma: no cover |
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pass |
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class ObservableFactory(Protocol): |
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"""Async ObservableFactory Protocol. |
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Define function which create Observable. |
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""" |
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async def __call__(self) -> Observable: # pragma: no cover |
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"""Create an Observable. |
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Returns: |
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(Observable): the new observable instance. |
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""" |
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pass |
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class Subject(Observable, Observer, Protocol): |
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"""A Subject is like an Observable, but can multicast to many Observers. |
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Subjects are like EventEmitters: they maintain a registry of many listeners. |
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""" |
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pass |
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class SubjectEventHandler(Protocol): |
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"""Subject Event Handler Procotol.""" |
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async def __call__(self, count: int, source: Observer) -> None: # pragma: no cover |
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pass |
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class SubjectHandler(Protocol): |
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"""Subscribe Handler Protocol. |
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This handler could be called on subscription/unsubscribe event. |
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""" |
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async def on_subscribe(self, count: int, source: Observer) -> None: # pragma: no cover |
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"""Notify on subscribe event. |
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Args: |
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count (int): current #subscribers after subscription |
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source (Observer): observer source |
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""" |
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pass |
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async def on_unsubscribe(self, count: int, source: Observer) -> None: # pragma: no cover |
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"""Notify on unsubscribe event. |
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Args: |
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count (int): current #subscribers after unsubscribe |
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source (Observer): observer source |
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""" |
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pass |
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class SubjectFactory(Protocol): |
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def __call__(self, subject_handler: Optional[SubjectHandler] = None) -> Subject: # pragma: no cover |
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pass |
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class ConnectHandler(Protocol): |
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"""Connect Handler Protocol.""" |
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async def __call__(self) -> Subscription: # pragma: no cover |
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pass |
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class RefCountHandler(Protocol): |
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"""RefCount Handler Protocol.""" |
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async def __call__(self) -> Observable: # pragma: no cover |
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pass |
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class ConnectableObservable(Observable, Protocol): |
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"""Define a connectable observable protocol. |
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We have : |
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- subscribe function (it's an observable) |
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- connect function: start executing |
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- ref_count function: makes the Observable automatically start executing |
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when the first subscriber arrives, |
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and stop executing when the last subscriber leaves. |
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""" |
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async def connect(self) -> Subscription: # pragma: no cover |
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"""Connect.""" |
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pass |
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async def ref_count(self) -> Observable: # pragma: no cover |
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"""Reference counter. |
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Make the multicasted Observable automatically start executing when |
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the first subscriber arrives, |
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and stop executing when the last subscriber leaves. |
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""" |
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pass |
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class ConnectableObservableEventHandler(Protocol): |
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"""Connectable Observable Event Handler Protocol.""" |
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async def __call__(self) -> None: # pragma: no cover |
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pass |
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class ConnectableObservableHandler(Protocol): |
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"""Connectable Observable Handler Protocol. |
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This handler could be called on conect/disconnect event. |
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""" |
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async def on_connect(self) -> None: # pragma: no cover |
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"""Called on connect event.""" |
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pass |
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async def on_disconnect(self) -> None: # pragma: no cover |
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"""Called on disconnect event.""" |
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pass |
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class _AsyncAccumulatorOperator(Protocol[T]): |
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"""Async Accumulator Operator Protocol. |
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Accumulator are used in reduce operation. |
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""" |
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async def __call__(self, buffer: T, item: T) -> T: # pragma: no cover |
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pass |
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class _SyncAccumulatorOperator(Protocol[T]): |
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"""Async Accumulator Operator Protocol. |
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Accumulator are used in reduce operation. |
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""" |
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def __call__(self, buffer: T, item: T) -> T: # pragma: no cover |
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pass |
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AccumulatorOperator = Union[_AsyncAccumulatorOperator, _SyncAccumulatorOperator] |
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"""Accumulator Operator Protocol. |
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Accumulator are used in reduce operation. |
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""" |
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class _AsyncPredicateOperator(Protocol): |
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"""Async Predicate Operator Protocol. |
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Predicate are used in filter operation. |
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""" |
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async def __call__(self, item: Any) -> bool: # pragma: no cover |
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pass |
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class _SyncPredicateOperator(Protocol): |
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"""Sync Predicate Operator Protocol. |
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Predicate are used in filter operation. |
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""" |
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def __call__(self, item: Any) -> bool: # pragma: no cover |
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pass |
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PredicateOperator = Union[_AsyncPredicateOperator, _SyncPredicateOperator] |
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"""Predicate Operator Protocol. |
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Predicate are used in filter operation. |
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""" |
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