public function extractFullyQualifiedClassName()
    {
        $fullyQualifiedClassName = $this->extractClassName();
        if ($fullyQualifiedClassName === null) {
            return null;
        }
        $namespace = $this->extractNamespace();
        if ($namespace !== null) {
            $fullyQualifiedClassName = $namespace . '\\' . $fullyQualifiedClassName;
        }
        return $fullyQualifiedClassName;
    }