Design Patterns Quick Memo

[Creational Patterns]

Abstract factory: use generic interface, client doesn't know which concrete class is being instantiated

Builder: step by step build something, example: building a house, making subway sandwich

Factory:

prototype: 从现有的几个代表形clone新的, example: map editor

singleton:仅一个instance。。static元素的继承问题？？

[Structural Patterns]

adapter: 把不同的接口适应化

bridge：分离主体和具体的implemenation, example：问卷调查template＋具体问卷问题

composite: 文件和文件的相互包含和层级关系, example: 文件系统

decorator:不同的窗口的美化，scroller/frame，添加一个水平线在subclass

facade:加一个统一的中间接口，隔离外界和子系统，e.g. compiler system

flight weight, 游戏引擎中对sprite的复用, reuse state，event

proxy: e.g.编辑器／浏览器里，读取图像文件失败时显示的红叉叉

[Behavioral Patterns]

chain of responsibility: one of the item in the open list is gonna handle the problem, which is opaque to the outside

command: queue/log request, a list/buffer..

interpreter: regex

iterator: traverse stuff， C++ STL, Java

mediator:租房，求房，（同辈之间）透过中介的关系； 按钮被另一个组建dictates

memento: save/screen shot a particular state of the subject

observer(subscription): flash, eventlistener thing; C++, delegation.

state: multiply states act according to same interface(e.g. TCPState, GameState, AI, animation tree)

strategy: a family of algorithm to solve a certain problem, encapsulated each one.  (e.g. textEditor, linebreaker??)

http://en.wikipedia.org/wiki/Strategy_pattern

template method: the most basic/common use of inheritance

Visitor: allow outside functionalities to be executed

class Element {
　　Accept(Visitor visitor)  {
　　　　visitor.Visit(this);
　　}
}

class Visitor {
　　Visit(Element element) {
　　　　//Do something
　　　　...　　
　　}
}

(NOTICE: while virtual functions are dispatched dynamically in C++, function overloading is done statically.)