月份：2006年12月

Thinking in Patterns with Java V0.9: Chapter 14: Algorithmic partitioning: TIPatterns.htm#_Toc41169746

1, Sections:

Algorithmic partitioning  106

  Command: choosing the operation at run-time  106

    Exercises. 109

  Chain of responsibility. 109

    Exercises

2, The main content and feeling:

  1) Command pattern:

  It is "wrapping a method in an object". From my understanding, a Command is a very simple class with a sole method to resolve a specific task. When I perform a big task, I can put some of these Command objects together, and in a "manager" class, call these object's own sole method to perform its specific little task, and, in this way, to finish that big task through these little object's contributions.

 

  In my first touch of these patterns, I think there are clear differents between Command Pattern and Strategy Pattern:

  Command Pattern: Put serveral Command objects together to perform a common task, just like draw together to fight on a common enemy;

  Strategy Pattern: At a specific time use a specific Strategy to accomplish a different result.

  But, why does Bruce say below in the book:

 

I would hazard to say that Command provides flexibility while you’re writing the program, whereas Strategy’s flexibility is at run time. Nonetheless, it seems a rather fragile distinction.

 

  Maybe, Bruce describe it from the structural aspect, I look at them at the function's aspect.

  

  2) Chain of Responsibility:

  That just an "Expert System", there are several experts in this system, and, these experts wait here in line. When a problem come, from the first expert to the last expert, every expert try to resolve this problem. If one can't do it, then the problem be handed to the next expert, until the problem be rosolved or the last expert can't do it yet, then an un-resolved problem is retruned.

  From this view aspect, Chain of Responsibility just like an auto-selected Strategy Pattern: the method for resolving problem is auto selected in the former, and a manual-selected strategy used for a problem in the later.

  A question raises, what if the problem handed to the Expert System need serveral experts to resolve them respectively? Maybe, this problem need to be cuted into serveral little problems then hand them into the expert system successively.

  In this pattern, Bruce says GoF use many words to create an linked list to contain these "experts", it is because GoF wrote that Design Pattern at the time "before the Standard Template Library (STL) was incorporated into most C++ compilers'. But, in Java, a ready-made List is here.

  In fact, I need review these content when I finish the first reading of this book. So, although there are some place I can't understand it very clearly, but, I must go on, finish the first reading of entire book in shortest time is the most import thing. I just only read half of this book. After reading this book once, the J2EE Design Patterns need me to read. So, don't tie at any specific point, go! go! go!

3, Questions about programming:

  1), The point is to decouple the choice of function to be called from the site where that function is called.

  2),  something you can normally only do by writing new code but in the above example could be done by interpreting a script.

  3), What is the famous "callback" technique?

4, Questions about english language:

1), Strange words:

   functor, collectively, incorporated into, BabelFish, Bisection, ConjugateGradient, fragile

2), Difficult sentences:

On the other hand, with a Command object you typically just create it and hand it to some method or object, and are not otherwise connected over time to the Command object.

 

********************************************************************************************************

Class diagram of //: chainofresponsibility:FindMinima.java in section: Chain of responsibility

                                     incomplete

今天，有两个事情使我要写这篇日记。

1、某处元旦节庆祝。其中有两个小学二三年级的孩子唱歌和跳舞，唱的是S.H.E的《不想长大》，歌词是这样的：

... 我不想我不想不想长大 长大后世界就没有花 我不想我不想不想长大 我宁愿永远又笨又傻 我不想我不想不想长大 长大后我就会失去他 我深爱的他深爱我的他 已经变的不像他 ...

完整的见：

http://mp3.baidu.com/m?tn=baidump3lyric&word=%B2%BB%CF%EB%B3%A4%B4%F3&ct=150994944&lm=-1&lf=3

其中一个还跳着很成人的舞姿。

相反，有个成人上台表演跳的是很传统的蒙古草原舞蹈。

2、女儿让我给她买一种贴纸画，我不知道是哪种（后来知道是泡泡糖里的），就看了另外的贴纸画，清一色的是武侠小说里的人物：好像有：小龙女，小李飞刀什么的。听店主说，这种贴纸卖得很好。这个小店就紧挨着一个幼儿园。

而且，我想起现在许多小孩都在唱不是他们该唱的歌，看不是他们该看的漫画（尤其是有些日本的卡通漫画），这让我很想说：让孩子唱孩子应该唱的，玩孩子应该玩的吧。

在我的心里，孩子的世界应该是童话的、纯洁的世界。里面有灿烂的阳光、蓝蓝的天、绿绿的草、五颜六色的花，还有蝴蝶等。。。

但是，现实是严竣的，以上两个小事只是冰山一角。

难道，我们找不到给孩子唱的，给孩子玩的吗？我不这样认为。而且，我也不认为，孩子们就只有看外国动画、漫画（这段时间我们的孩子嘴里常念叨的是什么：奥特曼、迪克、超人、怪兽；葫芦娃也有提，时候不多；我想，我们从来没有给她看这些，一定是她的小朋友圈子中互相交流的热门主题，哪个最英雄，我要当奥特曼、超人，打怪兽...）。我们的血液里天生有一份最值钱的祖宗留下的、世界仅有的宝贵财富：5000年厚重的文化传承，这一点也可以说，中国人是世界最富有的人，我们应该为生为中国人而骄傲。

难道，这悠悠5000年的文化还找不到怎样来滋润孩子心灵的灵感和源泉吗？不会吧。我们完全可以以现代的科技，随便在5000年的历史长河中捡一点，就能做出至少是中国的唐老鸭和米老鼠，进一步，做成世界级的东西也不是没有可能。我们的东西有不少是外国人在发挥，像日本的三国文化（包括：游戏、漫画等），美国的花木兰，当然，应该还有太多，不过我没有去找，如果是专心去找，肯定有不少的。

作为一个家长、孩子的父亲，我希望我们的孩子能够唱他们该唱的、玩他们该玩的、看他们该看的。

Thinking in Patterns with Java V0.9: Chapter 13: Reducing interface complexity: TIPatterns.htm#_Toc41169743

1, Sections:

 Facade. 105

   Package as a variation of Facade  106

2, The main content and feeling:

  What is Facade? Bruce tell me:"If something is ugly, hide it inside an object.".

  After reading this chapter, I can got some below:

 

  1), Design pattern is really a pratical technique.

  Although I read this book, and know some of Facade, and know its example://:

facade:Facade.java, but, I feel I can't understand it without a real applying

of this pattern. Maybe, I will use it later.

  2), Just like Bruce's feeling:"To me, the Facade has a rather "procedural" (non-object-oriented) feel to it: you are just calling some functions to give you objects."

  3), Facade is most useful to C++ programmer, in java, "package" is a

build-in Facade.

 

3, Questions about programming:

  

  1), If it is that the function of Facade Pattern is only acting as a factory to create some objects? It can't call another object's method to process something in a static method just like below?

class A {   void f(){} } public class B {   static void doFinA() {     (new A()).f();   } }

  

Then, I can do something like this:

B.doFinA();

4, Questions about english language:

1), Strange words:

    cast about, mold, first-cut, tax adviser, tax code, mediator, as if, to be

fair, clash, majority

2), Difficult sentences:

 

                                     incomplete