June 2022
Beginner to intermediate
672 pages
17h 23m
Japanese
Content preview from Head Firstデザインパターン 第2版 ―頭とからだで覚えるデザインパターンの基本
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you are here
267
7
章
Adapter
パターンと
Facade
パターン
最小知識の原則（
Principle
of Least Knowledge
）
最小知識の原則は、オブジェクト間のやり取りを少数の身
近な「友達」だけに減らすようにするという指針です。この
原則は通常、以下のように表現されます。
実際にこれはどういう意味でしょうか？
システムを設計す
る際には、すべてのオブジェクトについて、やり取りするク
ラスの数に注意し、そのクラスとどのようにやり取りするか
についても注意してください、という意味です。
この原則により、多数のクラスが互いに結合し、システム
のある部分に対する変更が他の部分にも連鎖してしまうよう
な設計を回避できます。多くのクラスの間に多くの依存関係
があると、保守コストがかかり他者が理解しにくい脆弱なシ
ステムを構築することになってしまいます。
このコードが結合しているクラスの数はいくつでしょうか？
public float getTemp() {
return station.getThermometer().getTemperature();
}
設計原則
最小知識の原則：直接の友達と
だけやり取りする。
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.