/**
  * carry out the search and execute it
  */
 function perform()
 {
     $search = new SearchEngine();
     // execute the search and check if there is any result
     $results = $search->siteSearch($this->_searchTerms);
     if (!$results || empty($results)) {
         // if not, then quit
         $this->_view = new SummaryView("summaryerror");
         $this->_view->setErrorMessage($this->_locale->tr("error_no_search_results"));
         return false;
     }
     // but if so, then continue...
     $this->_view = new SummaryView("searchresults");
     $this->_view->setValue("searchresults", $results);
     $this->setCommonData();
     return true;
 }