public function getDirectives()
    {
        if ($this->directives === null) {
            $this->directives = array();
            foreach ($this->parseParams() as $collection) {
                foreach ($collection as $key => $value) {
                    $this->directives[$key] = $value === '' ? true : $value;
                }
            }
        }

        return $this->directives;
    }