public function getUsedClassesInClass($classFile)
    {
        $useResult = array();
        $content = $this->getFileContent($classFile);
        if (preg_match_all('/(use\s+)(.*)(;)/', $content, $useResult) && 4 === count($useResult)) {
            // @todo: use keyName based result check instead of index!
            return ($useResult[2]);
        }

        return null;
    }