/**
  * checks wether a single condition is fulfilled
  * every trigger object type must implement a static method
  * _checkCondition($a_operator, $a_value)
  */
 function _checkCondition($a_id, $a_usr_id = 0)
 {
     global $ilUser;
     $a_usr_id = $a_usr_id ? $a_usr_id : $ilUser->getId();
     $condition = ilConditionHandler::_getCondition($a_id);
     switch ($condition['trigger_type']) {
         case "tst":
             include_once './Modules/Test/classes/class.ilObjTestAccess.php';
             return ilObjTestAccess::_checkCondition($condition['trigger_obj_id'], $condition['operator'], $condition['value'], $a_usr_id);
         case "crs":
             include_once './Modules/Course/classes/class.ilObjCourse.php';
             return ilObjCourse::_checkCondition($condition['trigger_obj_id'], $condition['operator'], $condition['value'], $a_usr_id);
         case 'exc':
             include_once './Modules/Exercise/classes/class.ilObjExercise.php';
             return ilObjExercise::_checkCondition($condition['trigger_obj_id'], $condition['operator'], $condition['value'], $a_usr_id);
         case 'crsg':
             include_once './Modules/Course/classes/class.ilObjCourseGrouping.php';
             return ilObjCourseGrouping::_checkCondition($condition['trigger_obj_id'], $condition['operator'], $condition['value'], $a_usr_id);
         case 'sahs':
             include_once './Services/Tracking/classes/class.ilLPStatus.php';
             return ilLPStatus::_lookupStatus($condition['trigger_obj_id'], $a_usr_id) == LP_STATUS_COMPLETED_NUM;
         case 'svy':
             include_once './Modules/Survey/classes/class.ilObjSurvey.php';
             return ilObjSurvey::_checkCondition($condition['trigger_obj_id'], $condition['operator'], $condition['value'], $a_usr_id);
         default:
             return false;
     }
 }