def require_methods(*method_args):
"""Class decorator to require methods on a subclass.
Example usage
------------
@require_methods('m1', 'm2')
class C(object):
'This class cannot be instantiated unless the subclass defines m1() and m2().'
def __init__(self):
pass
"""
def fn(cls):
orig_init = cls.__init__
def init_wrapper(self, *args, **kwargs):
for method in method_args:
if (not (method in dir(self))) or \
(not callable(getattr(self, method))):
raise Exception("Required method %s not implemented" % method)
orig_init(self, *args, **kwargs)
cls.__init__ = init_wrapper
return cls
return fn
Diff to Previous Revision
--- revision 1 2011-05-27 22:56:46
+++ revision 2 2011-05-27 23:52:28
@@ -5,7 +5,7 @@
------------
@require_methods('m1', 'm2')
class C(object):
- 'This class cannot be instantiated unless the subclass defines m1() and m2().
+ 'This class cannot be instantiated unless the subclass defines m1() and m2().'
def __init__(self):
pass
"""
