/**
  * get instance of specialized GUI class
  *
  * static
  */
 function &getInstance($a_id)
 {
     $object = new ilSCORMObject($a_id);
     switch ($object->getType()) {
         case "sit":
             // item
             $item =& new ilSCORMItemGUI($a_id);
             return $item;
             break;
         case "sos":
             // organizations
             $sos_gui =& new ilSCORMOrganizationsGUI($a_id);
             return $sos_gui;
             break;
         case "sor":
             // organization
             $sor_gui =& new ilSCORMOrganizationGUI($a_id);
             return $sor_gui;
             break;
         case "sma":
             // manifest
             $sma_gui =& new ilSCORMManifestGUI($a_id);
             return $sma_gui;
             break;
         case "srs":
             // resources
             $srs_gui =& new ilSCORMResourcesGUI($a_id);
             return $srs_gui;
             break;
         case "sre":
             // resource
             $sre_gui =& new ilSCORMResourceGUI($a_id);
             return $sre_gui;
             break;
     }
 }