Being Studing Design Patterns

　　早就买了设计模式的书了，去年看了几个模式，就丢在书柜了，感觉当时自己不适合看那书。前几个月翻了一下 《Head Fisrt Design Partterns》，觉得自己可以开始看了。

　　结合GOF的《设计模式：可复用的软件基础》，看了前三份之一的《Design Patterns Explained》，对以前看的几个模式了解更深了。还在当前的项目中小用了一下，感觉还不错。前几天做的东西，需求一直要变，搞得我挺晕的。

　　为什么要学设计模式呢（转自《Design Patterns Explained》）：
It helps to

• Reuse existing, high-quality solutions to commonly recurring problems.

• Establish common terminology to improve communications within teams.

• Shift the level of thinking to a higher perspective.

• Decide whether I have the right design, not just one that works.

• Improve individual learning and team learning.

• Improve the modifiability of code.

• Facilitate adoption of improved design alternatives, even when patterns are not used explicitly.

• Discover alternatives to large inheritance hierarchies.

　　在面向对象设计方面，GOF有这么几个建议：

• Design to interfaces.

• Favor composition over inheritance.

• Find what varies and encapsulate it

还有：One place, One rule. 也就说: have only one place where you implement a rule.

还有好多，要好好看......