module ContentState  class Published < Base    include Singleton    def published?(content)      true    end    def enter_hook(content)      super      content[:published] = true      content[:published_at] ||= Time.now    end    def change_published_state(content, boolean)      if ! boolean        content[:published] = false        content[:published_at] = nil        content.state = Factory.new(:just_withdrawn)      end    end    def withdraw(content)      content.state = Factory.new(:just_withdrawn)    end    def set_published_at(content, new_time)      content[:published_at] = new_time      return if new_time.nil?      if new_time > Time.now        content.state = PublicationPending.instance      end    end  endend