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"""Subject utilities.""" |
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from collections import namedtuple |
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from .definition import CompleteHandler, ErrorHandler, NextHandler, Subject, SubjectEventHandler, SubjectHandler, Subscribe |
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from .observer import default_error, default_on_completed |
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__all__ = ["subject_handler", "subject"] |
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SubjectDefinition = namedtuple("SubjectDefinition", ["subscribe", "on_next", "on_error", "on_completed"]) |
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"""Implements Subject Protocol.""" |
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SubjectHandlerDefinition = namedtuple("SubjectHandlerDefinition", ["on_subscribe", "on_unsubscribe"]) |
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"""Implements SubjectHandler Protocol.""" |
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def subject( |
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subscribe: Subscribe, on_next: NextHandler, on_error: ErrorHandler = default_error, on_completed: CompleteHandler = default_on_completed |
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) -> Subject: |
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"""Build a subject. |
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The underlying implementation use an named tuple. |
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Args: |
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subscribe (Subscribe): subscription handler. |
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on_next (NextHandler): on_next handler which process items |
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on_error (ErrorHandler): on_error handler (default with default_error |
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which raise Exception) |
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on_completed (CompleteHandler): on_completed handler (default with noop) |
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Returns: |
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(Subject): a subject |
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""" |
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return SubjectDefinition(subscribe=subscribe, on_next=on_next, on_error=on_error, on_completed=on_completed) |
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def subject_handler(on_subscribe: SubjectEventHandler, on_unsubscribe: SubjectEventHandler) -> SubjectHandler: |
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"""Create a SubjectHandler. |
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Args: |
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on_subscribe (SubjectEventHandler): on subscribe event handler |
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on_unsubscribe (SubjectEventHandler): on unsubscribe event handler |
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Returns: |
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(SubjectHandler): a SubjectHandler instance. |
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""" |
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return SubjectHandlerDefinition(on_subscribe=on_subscribe, on_unsubscribe=on_unsubscribe) |
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