设计模式学习3

17:访问者模式(Visitor pattern)
   Visitor,ConcreteVisitor,Element,ConcreteElement(Implement accept method, normally use visitor.visit(this))
18:状态模式(State pattern)
19:原型模式(Prototype patern)
  Implements Cloneable。Do not run the construct method when clone.
  1:simply clone:do not clone array and reference object but can clone others variable
   2:deeply clone:use array.clone.
20:中介者模式(Mediator pattern)
MVC
21:解释器模式(Interpreter pattern)
22:亨元模式(Flyweight pattern)
23:备忘录模式(Memento pattern)