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from typing import Type |
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from .base import _LOGGED_VALUE__PROPERTY_NAME, _LOGGED_MODEL__PROPERTY_ATTR_PREFIX, _ValueType |
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from .data import TimeRangedData |
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class LoggedValue: |
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""" |
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Overview: |
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LoggedValue can be used as property in LoggedModel, for it has __get__ and __set__ method. |
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This class's instances will be associated with their owner LoggedModel instance, all the LoggedValue |
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of one LoggedModel will shared the only one time object (defined in time_ctl), so that timeline can |
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be managed properly. |
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Interfaces: |
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``__init__``, ``__get__``, ``__set__`` |
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Properties: |
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- __property_name (:obj:`str`): The name of the property. |
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""" |
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def __init__(self, type_: Type[_ValueType] = object): |
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""" |
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Overview: |
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Initialize the LoggedValue object. |
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Interfaces: |
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``__init__`` |
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""" |
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self.__type = type_ |
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@property |
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def __property_name(self): |
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""" |
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Overview: |
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Get the name of the property. |
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""" |
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return getattr(self, _LOGGED_VALUE__PROPERTY_NAME) |
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def __get_ranged_data(self, instance) -> TimeRangedData: |
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""" |
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Overview: |
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Get the ranged data. |
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Interfaces: |
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``__get_ranged_data`` |
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""" |
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return getattr(instance, _LOGGED_MODEL__PROPERTY_ATTR_PREFIX + self.__property_name) |
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def __get__(self, instance, owner): |
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""" |
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Overview: |
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Get the value. |
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Arguments: |
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- instance (:obj:`LoggedModel`): The owner LoggedModel instance. |
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- owner (:obj:`type`): The owner class. |
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""" |
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return self.__get_ranged_data(instance).current() |
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def __set__(self, instance, value: _ValueType): |
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""" |
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Overview: |
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Set the value. |
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Arguments: |
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- instance (:obj:`LoggedModel`): The owner LoggedModel instance. |
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- value (:obj:`_ValueType`): The value to set. |
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""" |
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if isinstance(value, self.__type): |
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return self.__get_ranged_data(instance).append(value) |
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else: |
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raise TypeError( |
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'New value should be {expect}, but {actual} found.'.format( |
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expect=self.__type.__name__, |
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actual=type(value).__name__, |
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) |
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) |
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