public function convert($source)
{
$indices = [];
$xpath = new \DOMXPath($source);
$indexSearchPath = sprintf("/%s/%s", self::ROOT_NODE_NAME, self::INDEX_NODE_TYPE);
foreach ($xpath->query($indexSearchPath) as $indexNode) {
$indexIdentifier = $indexNode->getAttribute('identifier');
$indices[$indexIdentifier] = $this->parseIndexConfig($xpath, $indexNode);
}
return $indices;
}