private function getChildIterator(PuliResource $resource)
    {
        $staticPrefix = rtrim($resource->getPath(), '/').'/';
        $regExp = '~^'.preg_quote($staticPrefix, '~').'[^/]+$~';

        return new RegexFilterIterator(
            $regExp,
            $staticPrefix,
            new ArrayIterator($this->resources),
            RegexFilterIterator::FILTER_KEY
        );
    }