A simple decorator that helps define abstract methods: when such a method is called, an appropriate exception is raised.
Python, 32 lines
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Copy to clipboard1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | def abstractmethod(method):
def default_abstract_method(*args, **kwargs):
raise NotImplementedError('call to abstract method ' + repr(method))
default_abstract_method.__name__ = method.__name__
return default_abstract_method
if __name__ == '__main__':
class A:
@abstractmethod
def foo(self, data): pass
class B(A):
def foo(self, data):
self.data = data
a = A()
b = B()
b.foo(5)
exception_raised = False
try:
a.foo(3)
except NotImplementedError:
exception_raised = True
assert exception_raised
print 'OK'
|
I find it more consistent that the (nonetheless elegant): def foo(self): abstract
Why not raise built-in NotImplementedError?
Good idea, didn't know about that.
The only drawback to this approach is you won't fail withTypeError for incorrect arguments being passed.