*
 * <p>
 * It also allows defining field rules using XPath expressions to extract specific data from the XML document and map it to fields in the ResultData.
 * The extracted data is then formatted into an XML structure suitable for indexing.
 * </p>
 *
 * <p>
 * The class uses a cache for XPathAPI objects to improve performance. The cache duration is configurable.
 * </p>
 *
 * <p>