BT

New Early adopter or innovator? InfoQ has been working on some new features for you. Learn more

You are now in FULL VIEW
CLOSE FULL VIEW

SOLID Software and Design Patterns for Mere Mortals
Recorded at:

| by Phil Japikse on Sep 09, 2011 |
01:03:18

Summary
Phil Japikse explains SOLID software principles - Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion- and how to apply them using design patterns.

Sponsored Content

Bio

Phil Japikse is a Microsoft MVP and also holds MCSD, MCDBA, CSM, and CSP certifications. He has spoken at Code Camps and Days of .NET and is the Lead Director for the Cincinnati .Net User’s Group. Phil works as the Patterns and Practices Evangelist for Telerik (www.telerik.com). You can follow Phil on twitter via www.twitter.com/skimedic and read his blog at www.skimedic.com/blog.

Code PaLOUsa is a conference designed to cover all aspects of software development regardless of technology stack. It has sessions revolving around Microsoft, Java, and other development platforms; along with session on higher levels that are platform agnostic. The conference schedule will feature presentations from well-known professionals in the software development community.

Hello stranger!

You need to Register an InfoQ account or or login to post comments. But there's so much more behind being registered.

Get the most out of the InfoQ experience.

Tell us what you think

Allowed html: a,b,br,blockquote,i,li,pre,u,ul,p

Email me replies to any of my messages in this thread
Community comments

Barbara Liskov is a "she" by Chris Sutton

en.wikipedia.org/wiki/Barbara_Liskov

Barbara was referred to as a "he" several times during this talk.
  • Like
  • Reply
  • Back to top

ok... by Ranjix ranjix

1. for the "many methods with 4-5 lines of code", answer shouldn't be "well, what you want, a method with thousands lines of code", there is some granularity between the 2 extremes described, the talent is in finding that balance between size (of methods) and number (of methods), in such way that the balance still makes sense (semantically) and the code is readable.
2. "make a method do ONE thing well" is ambiguous. A method which calls 2 methods that each do ONE thing well, will do TWO things, unless you define doing the 2 things as doing 1. Maybe for you it's clear what you mean, sorry, for me isn't.
3. instills a fear of change which shouldn't really exist, the changes are the only constant thing, right?
5. the liskov principle is a nice one, nobody actually implements it as it's stated (possibly Eiffel, with the postconditions). Overriding shouldn't be allowed in case the principle is enforced (the behavior of a method between child and parent classes differs, hence they can't really be "substitutable").
6. there is a good undertone of "think before you apply".
7. the rest is ok, but again, unconvincing.
Just my 2 cents.
  • Like
  • Reply
  • Back to top

Re: ok... by Ranjix ranjix

for some reason I deleted the 4. in the above list.
4. "no plans survive the first battle", the same applies to all the "smart, beautiful, elegant" APIs I ran into, after a while (think years) they became ugly, tired, useless and in general obnoxious.
  • Like
  • Reply
  • Back to top

video is slow in China. by Meng Jian

Does infoq use any CDN?
  • Like
  • Reply
  • Back to top

Re: ok... by Edson Chavez

about 2: Uncle Bob wrote in clean code book : "if a function does only those steps that are one level of abstraction below the stated name of the function, then the function is doing one thing. After all, the reason we write functions is to decompose a larger concept (in other words the name of the function) int a set of steps at the next level of abstraction"

Regards
Grubhart
  • Like
  • Reply
  • Back to top

Re: ok... by Ranjix ranjix

well, both the presenter and uncle bob are right (and I actually do understand what the presenter stated), unfortunately the wording is not great in either case. In case of the presentation, is not the "number" of things that is the problem ("that number must be 1"), but is the purpose of things which matters, a method should do only and strictly what's required of it and nothing else ("what's required" is a different issue which needs a better definition). In case of uncle bob (how is uncle bob?), is difficult to think in terms of "how many levels of abstraction" are between certain things, and make sure that the number is 1, so it's not really helpful either (for example, how many levels of abstractions are between a method that saves an object and a method that calls a SQL statement? my personal answer is "who the hell knows?").
IMO in both cases someone tries (too hard) to extract some smarty-pants "principles" from a fairly down-to-earth example, and, in doing so, lose or hide the meaning.
  • Like
  • Reply
  • Back to top

Double Checked Locking might be broken by Fernando Cardoso

For Java, one should keep in mind that this double checked locking for Singleton creation might be broken.
www.cs.umd.edu/~pugh/java/memoryModel/DoubleChe...
  • Like
  • Reply
  • Back to top

Re: Double Checked Locking might be broken by Luis Espinal

For Java, one should keep in mind that this double checked locking for Singleton creation might be broken.
www.cs.umd.edu/~pugh/java/memoryModel/DoubleChe...


Uh, that was solved almost 8 years ago with Java 5.
  • Like
  • Reply
  • Back to top

Allowed html: a,b,br,blockquote,i,li,pre,u,ul,p

Email me replies to any of my messages in this thread

Allowed html: a,b,br,blockquote,i,li,pre,u,ul,p

Email me replies to any of my messages in this thread

8 Discuss

Sponsored Content

Login to InfoQ to interact with what matters most to you.

Forgot password ? Dont have an account? Register Here

Recover your password...

Back to login Dont have an account? Register Here
Follow

Follow your favorite topics and editors

Quick overview of most important highlights in the industry and on the site.

Like

More signal, less noise

Build your own feed by choosing topics you want to read about and editors you want to hear from.

Notifications

Stay up-to-date

Set up your notifications and dont miss out on content that matters to you

BT

We notice you're using an ad blocker

We understand why you use ad blockers. However to keep InfoQ free we need your support. InfoQ will not provide your data to third parties without individual opt-in consent. We only work with advertisers relevant to our readers. Please consider whitelisting us.