Используя шаблон «Строитель»

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Example of `builder' design pattern
class Director:
 """ Controls the construction process.
 Director has a builder associated with him. Director then
 delegates building of the smaller parts to the builder and
 assembles them together.
 """
 __builder = None
 def setBuilder(self, builder):
 self.__builder = builder
 # The algorithm for assembling a car
 def getCar(self):
 car = Car()
 # First goes the body
 body = self.__builder.getBody()
 car.setBody(body)
 # Then engine
 engine = self.__builder.getEngine()
 car.setEngine(engine)
 # And four wheels
 i = 0
 while i < 4:
 wheel = self.__builder.getWheel()
 car.attachWheel(wheel)
 i += 1
 return car
# The whole product
class Car:
 """ The final product.
 A car is assembled by the `Director' class from
 parts made by `Builder'. Both these classes have
 influence on the resulting object.
 """
 def __init__(self):
 self.__wheels = list()
 self.__engine = None
 self.__body = None
 def setBody(self, body):
 self.__body = body
 def attachWheel(self, wheel):
 self.__wheels.append(wheel)
 def setEngine(self, engine):
 self.__engine = engine
 def specification(self):
 print "body: %s" % self.__body.shape
 print "engine horsepower: %d" % self.__engine.horsepower
 print "tire size: %d\'" % self.__wheels[0].size
class Builder:
 """ Creates various parts of a vehicle.
 This class is responsible for constructing all
 the parts for a vehicle.
 """
 
 def getWheel(self): pass
 def getEngine(self): pass
 def getBody(self): pass
class JeepBuilder(Builder):
 """ Concrete Builder implementation.
 This class builds parts for Jeep's SUVs.
 """
 def getWheel(self):
 wheel = Wheel()
 wheel.size = 22
 return wheel
 def getEngine(self):
 engine = Engine()
 engine.horsepower = 400
 return engine
 def getBody(self):
 body = Body()
 body.shape = "SUV"
 return body
class NissanBuilder(Builder):
 """ Concrete Builder implementation.
 This class builds parts for Nissan's family cars.
 """
 def getWheel(self):
 wheel = Wheel()
 wheel.size = 16
 return wheel
 def getEngine(self):
 engine = Engine()
 engine.horsepower = 85
 return engine
 def getBody(self):
 body = Body()
 body.shape = "hatchback"
 return body
# Car parts
class Wheel:
 size = None
class Engine:
 horsepower = None
class Body:
 shape = None
def main():
 jeepBuilder = JeepBuilder()
 nissanBuilder = NissanBuilder()
 director = Director()
 # Build Jeep
 print "Jeep"
 director.setBuilder(jeepBuilder)
 jeep = director.getCar()
 jeep.specification()
 print ""
 # Build Nissan
 print "Nissan"
 director.setBuilder(nissanBuilder)
 nissan = director.getCar()
 nissan.specification()
if __name__ == "__main__":
 main()