[Python-pattern design] Factory method pattern

[转载]: http://whilefalse.net/2009/10/21/factory-pattern-python-__new__/

Python中Factory method的使用借鉴

class Winter(object):    def display(self):        print 'Winter'class Summer(object):    def display(self):        print 'Summer'class Autumn(object):    def display(self):        print 'Autumn'class Spring(object):    def display(self):        print 'Spring'class Season(object):    seasons = {'winter': Winter, 'summer': Summer, 'autumn': Autumn, 'spring': Spring}        def __new__(cls,season):        print "creating a new season %s" % season        return Season.seasons[season]() def testSeason():    s = Season('winter')    s.display()       if __name__ == '__main__':    testSeason()