Martin Fowler's article & big problems

[quartz]

It took me a while, but I finally read it...

Martin Fowler's article is horrible! At the company I work the "service locator pattern" is used instead of dependency injection. Bad Bad Bad.

As a result, when I had to reuse some classes from the main project in a smaller tool, and instead of using the 17 classes I needed, I had to import 350 classes with LOTS of bugs in it, because the service locator had dependencies to it! Completely pointless! Dep Inj decreses the coupling, service locator increases it.

In his examples he even implies the locators SHOULD have static class links, and his "interface for locators" solution is completely unclear.

I completely lost respect for Fowler after that one.

[quartz]

Finally, he doesn't explain why "...(Dependency Injection) tends to be hard to understand and leads to problems when you are trying to debug." He just says it, no backing up whatsoever. He DOES mention that "with a Service Locator every user of a service has a dependency to the locator".

More Dependency = More Coupling = lower software quality. Basic software metrics.

[Chris]

Please post the link to the article you are refering to.

thanks,
Chris

[gpoirier]

I assume he's refering to this article: http://martinfowler.com/articles/injection.html

[quartz]

I assume he's refering to this article: http://martinfowler.com/articles/injection.html

Exactly, sorry for missing such an important fact too!

[Rod Johnson]

I have a lot of respect for Martin, but I agree with some of these criticisms of that article. In my experience, there are huge problems with service location in large applications. That article is far from the best material on this topic. I described the value proposition of DI (before the label, of course) in much more detail in Expert One-on-One J2EE Design and Development over a year earlier.

[pigasus]

That article is far from the best material on this topic.

I'm a fan of Dependency Injection, but I'm always interested in good discussions of other points of view -- did you have a specific source in mind as better or better still, the best?

[Rod Johnson]

Well I've written two books that cover it, which both go into more detail... Expert J2EE Design and Development and J2EE without EJB.

[tatvamasi]

No, you are already rich owning Interface21, I am not making you more rich.

[Arno Werr]

No, you are already rich owning Interface21, I am not making you more rich.

Get his books and read them. You'll make richer yourself intellectually.
I have those two (love them) and 'Professional Java Development with Spring'.

Hey, Rod, anything in works? Looking forward to your next treatise.
Gonna have it!!!