This week the Semantic Web company Sindice released SIREn, a new semantic search plugin for Apache Lucene built on top of Apache Solr.
“While Lucene has long offered these capabilities, its native capabilities are not intended for large semi-structured document collections (or documents with very different schemas),” the project website says. “For this reason we developed SIREn – Semantic Information Retrieval Engine – a Lucene plugin to overcome these shortcomings and efficiently index and query RDF, as well as any textual document with an arbitrary amount of metadata fields.”