画出创建型设计模式的类图

工厂方法 Factory Method

Define an interface for creating an object. but let subclasses decide which class to instantiate.

Factory Method lets a class defer instantiation to subclasses.

抽象工厂 Abstract Factory

Provide an interface for creating families of related or dependent objects without specifying their concrete classes. 

单例模式 Singleton

Ensure a class only has one instance, and provide a global point of access to it.

建造者模式 Builder

Separate the construction of a complex object from its representation so that the same construction process can create different representations.

原型模式 Prototype

Specify the kinds of objects to create using a prototypical instance, and create new objects by coping this prototype.