46 lines
1.5 KiB
Python
46 lines
1.5 KiB
Python
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#
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# Copyright 2016 Keunhong Lee
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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from types import FunctionType
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from typing import Callable, TypeVar, Union
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_WrappedMethod = TypeVar("_WrappedMethod", bound=Union[FunctionType, Callable])
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def final(method: _WrappedMethod) -> _WrappedMethod:
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"""Decorator to indicate that the decorated method is finalized and cannot be overridden.
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The decorator code is executed while loading class. Using this method
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should have minimal runtime performance implications.
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Currently, only methods with @override are checked.
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How to use:
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from overrides import final
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class SuperClass(object):
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@final
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def method(self):
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return 2
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class SubClass(SuperClass):
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@override
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def method(self): #causes an error
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return 1
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:raises AssertionError: if there exists a match in sub classes for the method name
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:return: method
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"""
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setattr(method, "__final__", True)
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return method
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