EvoBal/app/mailboxes/in_mailbox.rb

class InMailbox < ApplicationMailbox
  def process
    email_importer = EmailImporter.new
    repository = EmailRepository.new
    rules_evaluator = RulesEvaluator.new

    email = email_importer.import(mail)

    RuleSet.enabled.each do |rule_set|
      if rules_evaluator.evaluate(email, rule_set)
        rule_set.actions.enabled.each do |action|
          klass = action.class_name.constantize
          email = klass.new.process(email)
        rescue NameError => ex
          # TODO: log a warning
        end
      end
    end

    repository.save(email)
  end
end