as per Initialize max value in Ruby on Rails ActiveRecord, automagically

Initialize max value the Server Way in a Fat Model, the server way, revised

def after_initialize
 if self.new_record? then
   if $item_sequence_order_max_value.nil? ||
    ( (!$item_display_order_max_dateTime.nil? )&& ( ( (Time.now - $item_display_order_max_dateTime).to_i ) > ( 10 *60 ) )) then
        $item_display_order_max_value = self.class.maximum('display_order')
        $item_display_order_max_value = 0 if $page_display_order_max_value.nil?  
      end
    $item_display_order_max_dateTime = Time.now
    $item_display_order_max_value += 1
    self.display_order = $item_display_order_max_value
    end
end

as per http://www.falsepositives.com/index.php/2010/08/23/initialize-max-value-in-ruby-on-rails-activerecord-automagically/ Initialize max value in Ruby on Rails ActiveRecord, automagically