Builder Pattern是一种独特的设计模式，有助于使用简单对象构建复杂对象并使用算法方法.这种设计模式属于创作模式的范畴.在此设计模式中，构建器类按步骤构建最终对象.此构建器独立于其他对象.
构建器模式的优点
它在构造和表示由类创建的指定对象之间提供清晰的分离和唯一层.
它可以更好地控制所创建模式的构造过程./p>
它提供了改变对象内部表示的完美场景.
如何实现构建器模式？
在本节中，我们将学习如何实现构建器模式.
class Director: __builder = None def setBuilder(self, builder): self.__builder = builder 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 productclass 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].sizeclass Builder: def getWheel(self): pass def getEngine(self): pass def getBody(self): passclass JeepBuilder(Builder): 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# Car partsclass Wheel: size = Noneclass Engine: horsepower = Noneclass Body: shape = Nonedef main(): jeepBuilder = JeepBuilder() # initializing the class director = Director() # Build Jeep print "Jeep" director.setBuilder(jeepBuilder) jeep = director.getCar() jeep.specification() print ""if __name__ == "__main__": main()
输出
上述程序生成以下输出 :
