Solr is a web services interface to Lucene. It is used in the Nines project, along with a user-presentation layer called Collex.
- Faceted browsing
- Performance enhancements
- Highlighting of matched terms in result sets
Solr vs. XTF:
- Solr has a web-based interface, while XTF is primarily commandline/filesystem.
- Solr can cache result sets for greater efficiency.
- XTF has dynaXML, which is very useful for processing XML content.