2.4 / October 4, 2018
|Platform||Java Virtual Machine|
Eclipse RDF4J (formerly OpenRDF Sesame) is an open-source framework for querying and analyzing RDF data. It was created by the Dutch software company Aduna as part of "On-To-Knowledge", a semantic web project that ran from 1999 to 2002. It contains implementations of an in-memory triplestore and an on-disk triplestore, along with two separate Servlet packages that can be used to manage and provide access to these triplestores, on a permanent server. The Sesame Rio (RDF Input/Output) package contains a simple API for Java-based RDF parsers and writers. Parsers and writers for popular RDF serialisations are distributed along with Sesame, and users can easily extend the list by putting their parsers and writers on the Java classpath when running their application.
Sesame supports two query languages: SPARQL and SeRQL. Another component of Sesame is Alibaba, an API that allows for mapping Java classes onto ontologies and for generating Java source files from ontologies. This makes it possible to use specific ontologies like RSS, FOAF and the Dublin Core directly from Java.
Sesame's RDF database API differs from comparable solutions in that it offers a stackable interface through which functionality can be added, and the storage engine (Storage and Inference Layer, SAIL) is abstracted from the query interface. Many other triplestores can be used through the Sesame API, including Ontotext GraphDB (built as a Sesame SAIL), Mulgara, and AllegroGraph. Through the stackable interface, functionality can be added to all of these stores. It can, for example, be used to add indexing and query capabilities to all compatible stores:
- Free text search capabilities can be added through the LuceneSail.
- Geospatial (GeoSPARQL) and free text search can be added through uSeekM.
In May 2016, Sesame officially forked into an Eclipse project called RDF4J, in recognition of Aduna no longer being involved in its development. This official fork brings the core developers with it and is supported by several commercial companies.