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Example 2

class Car:
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)


# === Car parts ===
class Wheel:
size = None


class Engine:
horsepower = None


class Body:
shape = None


class Director:
__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


class BuilderInterface:
def getWheel(self): pass
def getEngine(self): pass
def getBody(self): pass


class JeepBuilder(BuilderInterface):
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(BuilderInterface):
def getWheel(self):
wheel = Wheel()
wheel.size = 16
return wheel

def getEngine(self):
engine = Engine()
engine.horsepower = 100
return engine

def getBody(self):
body = Body()
body.shape = "hatchback"
return body
from CarBuilder import JeepBuilder, NissanBuilder, Director

d = Director()
d.setBuilder(JeepBuilder())
print(d.getCar())
d.getCar().specification()

d2 = Director()
d2.setBuilder(NissanBuilder())
print(d2.getCar())
d2.getCar().specification()