class_attr_lookup

For example, if I had a states table with the following values:

RUNNING
STARTING
STARTED
STOPPED
UNKNOWN
STOPPING

These values are used througout the database and the code as lookup values and my development database is not the same type of database as what is used in production, so rather than having to look them up each time because I can't count on the id being the same in all cases, I'm using State.running to represent the RUNNING record in the states table. Here's the code:

  
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  class Module
    def class_attr_lookup
      self.find(:all).each do |rec|
        r = rec.name.downcase.underscore
        self.class.send(:define_method, r) do
          self.class_eval "@@#{r}"
        end
        self.class_eval "@@#{r} = rec"
      end
    end
  end

I know that I could have used class_variable_get and class_variable_set, but I'm using both JRuby and MRI and at the time this was written there was a bug in JRuby and class_variable_get wasn't implemented. To use it, add class_attr_lookup to the model, like this:

  
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  class State < ActiveRecord::Base
    class_attr_lookup
    validates_presence_of :name
  end

Then to access the RUNNING record, you'd use State.running. Enjoy!