Lux - XML Search engine

Lux is an open source XML search engine using Lucene /Solr and Saxon XQuery/XSLT processor. Lux provides XML-aware indexing, an XQuery 1.0 optimizer that rewrites queries to use the indexes, and a function library for interacting with Lucene via XQuery. These capabilities are tightly integrated with Solr, and leverage its application framework in order to deliver a REST service, application server, and supporting tools.

Lux provides several kinds of index: XML full-text indexes, an XML path index, and configurable XPath indexes.