/**
  * This function returns a 'hilight' CSS class, used to hilight a given row in a table
  * There are currently (i.e defined in the CSS) 4 possible values HILIGHT_CLASS_CRITICAL,
  * HILIGHT_CLASS_WARNING, HILIGHT_CLASS_OK, HILIGHT_CLASS_NONE
  * To Be overridden by derived classes
  * @param void
  * @return String The desired higlight class for the object/row
  */
 public function GetHilightClass()
 {
     // Possible return values are:
     // HILIGHT_CLASS_CRITICAL, HILIGHT_CLASS_WARNING, HILIGHT_CLASS_OK, HILIGHT_CLASS_NONE
     $current = parent::GetHilightClass();
     // Default computation
     // Invoke extensions before the deletion (the deletion will do some cleanup and we might loose some information
     foreach (MetaModel::EnumPlugins('iApplicationUIExtension') as $oExtensionInstance) {
         $new = $oExtensionInstance->GetHilightClass($this);
         @($current = self::$m_highlightComparison[$current][$new]);
     }
     return $current;
 }