app/models/text_filter.rb


class TextFilter
  include Simpleton
  include Annotatable

  annotate :filter_name, :description

  def filter(text)
    text
  end

  class << self
    def inherited(subclass)
      subclass.filter_name = subclass.name.to_name('Filter')
    end

    def filter(text)
      instance.filter(text)
    end

    def descendants_names
      descendants.map { |s| s.filter_name }.sort
    end

    def find_descendant(filter_name)
      descendants.each do |s|
        return s if s.filter_name == filter_name
      end
      nil
    end
  end
end