public function execute()
 {
     $result = $this->getResult();
     $params = $this->extractRequestParams();
     $source = $target = null;
     if (isset($params['source']) && Language::isValidBuiltInCode($params['source'])) {
         $source = $params['source'];
     }
     if (isset($params['target']) && Language::isValidBuiltInCode($params['target'])) {
         $target = $params['target'];
     }
     $interval = $params['interval'];
     $result->addValue(array('query'), 'contenttranslationlangtrend', ContentTranslation\Translation::getTrend($source, $target, $interval));
 }