Delegation gives us monotonous codings. But, special method '__getattr__' is called when a certain object does not have the called method.
This recipe solve the tiresome coding. The object should call delegated object's method by argument 'name'.
Python, 30 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 | #!/usr/bin/env python
class Super:
def methodA(self):
print 'Super class methodA.'
class Delegated:
def methodA(self):
print 'Delegated class methodA.'
def methodB(self):
print 'Delegated class methodB.'
class X (Super):
def __init__(self, delegate=None):
self.delegate = delegate
def __getattr__(self, name):
return getattr(self.delegate, name)
delegated = Delegated()
x = X(delegated)
x.methodA()
x.methodB()
# Running this code.
# >> $ python delgate.py
# >> Super class methodA.
# >> Delegated class methodB.
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