76 lines
1.6 KiB
Python
76 lines
1.6 KiB
Python
class Null(object):
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"""
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A Null object class as part of the Null object design pattern.
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- External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Behavioral-Pattern-Usage}
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- External Null Object Pattern documentation: U{https://en.wikipedia.org/wiki/Null_Object_pattern}
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"""
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def __init__(self, *args, **kwargs):
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"""
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Do nothing.
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"""
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pass
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def __call__(self, *args, **kwargs):
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"""
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Do nothing.
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@return: This object instance.
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@rtype: Null
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"""
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return self
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def __getattr__(self, name):
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"""
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Do nothing.
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@return: This object instance.
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@rtype: Null
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"""
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return self
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def __setattr__(self, name, value):
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"""
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Do nothing.
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@return: This object instance.
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@rtype: Null
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"""
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return self
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def __delattr__(self, name):
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"""
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Do nothing.
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@return: This object instance.
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@rtype: Null
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"""
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return self
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def __repr__(self):
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"""
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Null object string representation is the empty string.
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@return: An empty string.
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@rtype: String
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"""
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return ''
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def __str__(self):
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"""
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Null object string representation is the empty string.
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@return: An empty string.
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@rtype: String
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"""
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return ''
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def __bool__(self):
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"""
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Null object evaluates to False.
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@return: False.
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@rtype: Boolean
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"""
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return False
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