public function active($pattern = null)
    {
        if (!is_null($pattern)) {
            $pattern = ltrim(preg_replace('/\/\*/', '(/.*)?', $pattern), '/');
            if (preg_match("@^{$pattern}\z@", Request::path())) {
                $this->activate();
            }

            return $this;
        }

        $this->attributes['class'] = Builder::formatGroupClass(array('class' => $this->builder->conf('active_class')), $this->attributes);
        $this->isActive = true;

        return $this;
    }