Comments on: Five Tips To Make Good Object-Oriented Code Better

By: Jon Wahl

Jon Wahl — Sun, 15 Nov 2009 17:56:45 +0000

I am a PHP developer who is keenly interested in fine tuning my object oriented programming skills. I write OO code (using the CodeIgniter framework), but I absolutely know that a lot of what I’m writing is not making use of the features of OO programming properly. I tend to write procedural code in my classes. I find object variables “handy” because they are global within the scope of the object. I really want to advance my skill/knowledge, but most of the articles written about object oriented programming in php tend to focus on the basics: What is object oriented programming; what are objects, methods, etc.. Your article was one of the first that addressed something I’m looking for: I understand the basics of OO programming but I want to do better. Do you know of any other online or book form resources that use php that addresses this?

Great article and great blog.

By: shfx

shfx — Wed, 04 Nov 2009 13:31:15 +0000

Thanks for the post. Those things are not so obvious until somebody write them down ;).

As for Dependency Injection, there is some nice interface at http://components.symfony-project.org/ but i never used it.

By: thinsoldier

thinsoldier — Fri, 30 Oct 2009 21:30:16 +0000

For so long I’ve only seen Dependency Injection mentioned in relation to Testing and (this sounds so bad) I’m honesly YEARS away from unit testing anything. So, I’ve just ignored DI. But now that you mention “feature addition” I suddenly realized that an old non-OO project of mine is full of “dependency injection” that I had to retrofit in order to add flexibility. I now see a ton of potential headaches in every piece of OO code I’ve written this year.

I’m hoping to soon have similarly enlightening moments for Interfaces, composition, factories, and coupling.

Your #1 point hit the nail on the head.
I spent the last 3 days trying to decide whether or not to bring a Value Object class into the picture for my database classes. In the end I chose not to.

Could you give an example of what the Zend Validate code would be like if it was too tightly coupled to the rest of ZFW.

By: Mikael

Mikael — Thu, 29 Oct 2009 07:55:49 +0000

Allright Brandon, so what you’re saying is sometimes people do one thing right (one object / one job) but end up doing another one wrong (tight coupling). For some reason, I was confused. Thanks for clarifying that for me.

By: Stephan Hochdoerfer

Stephan Hochdoerfer — Thu, 29 Oct 2009 07:47:00 +0000

Mentioning DI and ZF in one blog post seems really odd to me.

@David:
Maybe this helps as a starting point: http://en.wikipedia.org/wiki/Dependency_injection

By: Daniel Freudenberger

Daniel Freudenberger — Wed, 28 Oct 2009 23:16:36 +0000

Thanks for your post. I’d love to use DI in php but I didn’t find an easy to use DI-Implementation. I’m used to StructureMap in c# and I’m really loving it! Do you have any suggestions?

By: Anis uddin ahmad

Anis uddin ahmad — Wed, 28 Oct 2009 18:18:24 +0000

Thanks a lot for great tips!
Can u plz explain ‘one object – one job’ concept?
My view is :
An object is to represent the state and perform one/some related actions of an ‘Entity’. And each method of this objest should perform exactly ‘One job’.
Don’t u think so?

By: David Clark

David Clark — Wed, 28 Oct 2009 17:08:17 +0000

I always learn so much from your posts -thanks so much.
I do not know about dependency injection – do you have any links that do not require subscription?

By: Sergey

Sergey — Wed, 28 Oct 2009 17:00:52 +0000

> Zend Framework offers a good example of classes that are more loosely coupled. You can generally make use of Zend components without using the entire Zend Framework;

Haha((( do you ever tryed this? i tried to use Zend OpenId component without Zend Framework… oh, there was much easy to write new library((

By: ivanjovanovic

ivanjovanovic — Wed, 28 Oct 2009 16:46:05 +0000

Regarding the #5.

I see the properly designed application as pile of layers stacked one on other. Like the onion. When it comes to class design it must have only one function and to be just in one layer, not to be spread across them. Also, the connectivity among layers should be that you do not skip the layers. Information should flow through layers as Brandon is telling, without unnecessary couplings.

Cheers,
Ivan

By: Daniel

Daniel — Wed, 28 Oct 2009 14:10:12 +0000

Brandon,

Thanks for the write up I appreciated the read.

Daniel

By: Brandon Savage

Brandon Savage — Wed, 28 Oct 2009 13:39:24 +0000

For example, a developer will create an object that establishes a database connection, and another object which requests that database connection rather than allowing it to be injected. Or, they’ll create a request class (a class that holds the request data), but then have methods that send that data to the controller, rather than letting the controller request it. These are tight couplings that are unnecessary.

By: Mikael

Mikael — Wed, 28 Oct 2009 13:34:36 +0000

Hi Brandon,
I’m not sure I understand this

“Often times when a developer gives each object only one responsibility, they tightly couple objects together.”

Can you explain ?

Mikael