# ! /usr/bin/env python
# Lumberjack.py
# Author: D. Haynes
# 9th July 2002
#
# For more details on mix-ins, see
# http://www.linuxjournal.com/article.php?sid=4540
class CambridgeMan:
def roots(self):
return "But I'm forever a Cambridge Man"
class LumberjackInterface:
def __init__(self, methods):
self.methods = list(methods)
def __iter__(self):
return self
def next(self):
try:
return self.methods.pop(0)
except IndexError:
raise StopIteration
class LumberjackBase(CambridgeMan):
def __init__(self, name):
self.bases = self.__class__.__bases__
self.name = name
self.title = "Young %s" % self.name
def _mixIn(self, mixInClass):
self.__class__.__bases__ = (mixInClass,) + self.bases
mixInClass.__init__(self, self.name)
def Interface(self):
"""
Return a list of the names of the methods to be used by
the client.
"""
unpublishedMethods = ("roots", "Interface",
"WishIdBeenAGirlie")
methodType = type(self.Interface)
ifList = []
for i in dir(self):
if (type(getattr(self, i)) == methodType
and not i.startswith('_')):
ifList.append(i)
for i in unpublishedMethods:
ifList.remove(i)
return LumberjackInterface(ifList)
class RookieLumberjackMixIn:
"""
I cut down trees, I eat my lunch, I go to the lavatory.
On Wednesdays I go shopping, and have buttered scones for
tea...
"""
def __init__(self, name):
self.name = name
self.title = "Young %s" % self.name
def CutDownTrees(self):
return "%s cut down a tree." % self.name
def EatMyLunch(self):
return "%s eats his lunch." % self.name
def GoShopping(self):
return "%s has gone shopping." % self.name
def WishIdBeenAGirlie(self):
return 0
class SeasonedLumberjackMixIn:
"""
I cut down trees, I skip and jump, I like to press wild
flowers. I put on womens' clothing, and hang around in bars...
"""
def __init__(self, name):
self.name = name
self.title = "Head Lumberjack %s" % name
def CutDownTrees(self):
return "%s cut down a tree." % self.name
def SkipAndJump(self):
return "%s skips and jumps." % self.name
def HangAroundInBars(self):
return "%s is in the bar." % self.name
def WishIdBeenAGirlie(self):
return 0
class VeteranLumberjackMixIn:
"""
I cut down trees, I wear high heels, suspenders and a bra.
I wish I'd been a girlie, just like my dear Papa...
"""
def __init__(self, name):
self.name = name
self.title = "Old Man %s" % name
def CutDownTrees(self):
return "%s cut down a tree." % self.name
def WearHighHeels(self):
return "%s has stilletos on." % self.name
def WishIdBeenAGirlie(self):
return 1
class LumberjackFactory:
def __init__(self):
pass
def Lumberjack(self, name):
jack = LumberjackBase(name)
jack._mixIn(RookieLumberjackMixIn)
return jack
def display(jack):
print "I'm %s and I can..." % jack.title
for i in jack.Interface():
print i
print "And I do%s wish I was a girlie!" % ("n't" * (1 - jack.
WishIdBeenAGirlie()))
print
def do(jack):
for i in jack.Interface():
print apply(getattr(jack, i))
print
if __name__ == "__main__":
factory = LumberjackFactory()
jack = factory.Lumberjack("Jack")
display(jack)
do(jack)
jack._mixIn(SeasonedLumberjackMixIn)
display(jack)
do(jack)
jack._mixIn(VeteranLumberjackMixIn)
display(jack)
do(jack)
print jack.roots()
