The Tech Blog of Ken

Moving from Ant to Maven

I've made the switch from Ant to Maven at work. Ant is an extremely flexible and powerful tool, but I find that most of the time it's TOO flexible when you are working in an environment where you are doing complex builds.

Thinking back over half a decade of Ant scripts, I realize that I always spend a lot of time when I join a new project trying to understand a whole set of different Ant scripts and then getting all of them to look and work in a consistent way across all the components I'm building. Maven uses a standardized build process with hooks at each step in the process for you to customize or add your own behavior. Think about all those standard things you do for a build. Compile some source code, run some unit tests, create a test report, then create a package (jar, ear, whatever). A simple Maven build gives you all that stuff right out of the box, even without having to write any scripts.

The Maven home page uses some intimidating language - what's all this about a "Project Object Model"? That's enough to scare off any prospective user. A POM is simply an XML file where you put the basic information about your builds - jar dependencies, file names, etc - all the same stuff you would have in an Ant build script. It's all declarative, so you don't have to worry about the order of things (sounds like Ant in the early days). Maven uses standard conventions for directory structures to keep things simple to configure (no more arguing with your coworkers about whether to put your source code in 'src' or 'source' or 'java'), and to keep things the same between different build scripts. Of course, you can override these configurations, but it's better to go with the standard just for consistency.

I think some people are in a pretty good comfort zone with Ant and are afraid of learning a new tool for builds. But overall, I think it's faster and easier to start from scratch with Maven. If you're the type of person who likes the use of "convention over configuration" in Rails, then Maven is for you.

And BTW, if you're working with Rails, rake and Capistrano are no-brainers.

Technorati Tags: ant, maven

JRuby 0.9.0 released

JRuby 0.9.0 has been released - looks like it's getting really interesting:

"We are pleased to announce JRuby 0.9.0. This release has had so much activity and progress that we decided to bump things up to a 0.9.0 release. Many many bugs have been fixed to the point that:
RubyGems 0.9.0 installed and working*
WEBrick runs
Ruby on Rails runs on top of WEBrick (and generation scripts work)**
much improved YAML parser thanks to JvYAML and RbYAML projects
we bundle all non-native standard libraries in our distribution
We are getting to a correctness level where the more complicated Ruby libraries and applications are running properly. From this point on we are going to improve on correctness and start to focus more on performance.

For 0.9.1 we plan on getting Rails to run in a JEE servlet container out of the box. We also plan on improving Rake support. More correctness fixes will be applied as discovered."

Ruby on Rails LiveCD Linux distribution available

If you've been itching to try Rails, but have been avoiding it because you thought configuration might be a hassle, now there's a super easy way to get up and running. The Rails Live CD Linux distribution comes with Rails, MySQL, some editors and a whole suite of related tools to get you riding on Rails in a hurry. They even have a VMWare virtual machine so you can run the distribution in a window in your current OS.

I haven't tried it for myself yet, but the barrier to entry is so low I'm sure I'll do it soon. It's amazing how the LiveCD concept has applications that would never have emerged from a closed/proprietary software environment.

Annotate your Rails model classes with this plugin

One very nifty thing about Rails is that there are no intermediate ruby files for describing the database schema, since Rails loads the metadata at runtime and dynamically creates the model class attributes. Unfortunately, I often find myself browsing my database schema in phpMySql because I can't remember all the attributes off the top of my head, which interrupts my workflow because I have leave the editor to poke around in the database browser.

PragDave has created the AnnotateModels plugin for Rails, which adds a comment block at the top of your model classes describing the table structure and schema version (assuming you are using Rails migrations). Very handy. You'll see the source annotated with this plugin in the 2nd edition of the Agile Development with Rails book.

The plugin has recently been updated to also annotate YML test fixture files and also handles model files in subdirectories.