cache_sweeper

# File actionpack/lib/action_controller/caching/sweeping.rb, line 38
        def cache_sweeper(*sweepers)
          configuration = sweepers.extract_options!

          sweepers.each do |sweeper|
            ActiveRecord::Base.observers << sweeper if defined?(ActiveRecord) and defined?(ActiveRecord::Base)
            sweeper_instance = (sweeper.is_a?(Symbol) ? Object.const_get(sweeper.to_s.classify) : sweeper).instance

            if sweeper_instance.is_a?(Sweeper)
              around_filter(sweeper_instance, :only => configuration[:only])
            else
              after_filter(sweeper_instance, :only => configuration[:only])
            end
          end
        end