Wed Dec 26 16:00:00 GMT 2001

ShapeFactory1

#: c05:shapefact1:ShapeFactory1.py # A simple static factory method. from __future__ import generators import random class Shape(object): # Create based on class name: def factory(type): #return eval(type + "()") if type == "Circle": return Circle() if type == "Square": return Square() assert 1, "Bad shape creation: " + type factory = staticmethod(factory) class Circle(Shape): def draw(self): print "Circle.draw" def erase(self): print "Circle.erase" class Square(Shape): def draw(self): print "Square.draw" def erase(self): print "Square.erase" # Generate shape name strings: def shapeNameGen(n): types = Shape.__subclasses__() for i in range(n): yield random.choice(types).__name__ shapes = \ [ Shape.factory(i) for i in shapeNameGen(7)] for shape in shapes: shape.draw() shape.erase() #:~


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