protected function getClass($key, array $tokens)
    {
        $class = null;
        $tokenCount = count($tokens);
        for ($i = $key; $i < $tokenCount; $i++) {
            if ($this->isPartOfClass($tokens[$i])) {
                $class .= $tokens[$i][1];
            } elseif ($this->isWhitespace($tokens[$i])) {
                return $class;
            }
        }
    }