public function getClassNames ( $withNamespace = true ) {
        $tokens = new \PHP_Token_Stream($this->_content);
        $classes = $tokens->getClasses();
        $classNames = array();
        foreach ( $classes as $className => $class ) {
            $namespace = $class['package']['namespace'];
            if ( $withNamespace === true && $namespace !== '' ) {
                $className = $namespace . '\\' . $className;
            }
            $classNames[] = $className;
        }
        return $classNames;
    }