This post originated from an RSS feed registered with Ruby Buzz by David Heinemeier Hansson. Original Post: Validate models using code, not annotations Feed Title: Loud Thinking Feed URL: http://feeds.feedburner.com/LoudThinking Feed Description: All about the full-stack, web-framework Rails for Ruby and on putting it to good effect with Basecamp Latest Ruby Buzz Posts Latest Ruby Buzz Posts by David Heinemeier Hansson Latest Posts From Loud Thinking

Berin Loritsch is thinking about how to validate his domain models in Java. He's on the right track with his intention to shun the XML morass so commonly sought by the J-people, but unfortunately his ambitions stop short. He seems to be content with merely annotating his models with the validation rules instead of actually embedding them in code.

If he were using Rails, he'd be able to enjoy specifying validation rules using actual code in his Active Record objects. The following is not even a mock-up, I literally yanked part of the Account model in that next project I'm working on:

class Account < ActiveRecord::Base
  validates_presence_of     :subdomain, :name, :email_address, :password
  validates_uniqueness_of   :subdomain
  validates_acceptance_of   :terms_of_service, :on => :create
  validates_confirmation_of :password, :email_address, :on => :create
end

To me, this is beautiful. Programming poetry. Each method call reads like a sentence. "Account validates acceptance of terms of service on create". How can you not love that?

So please, aim higher. Annotations are a work-around for type system thats holding you back. Let it go. We'll be happy to help you transition out of the Sun and into the shade. Come join us in the Ruby on Rails community.