Table of Contents

1. Introduction

This guide collects links to Semantic Web toolkits for different programming languages. We evaluate for each toolkit:

• which features are offered (APIs, query languages, storage, reasoning support),
• the strength of the development effort (number of developers involved, latest release),
• the activity level of the toolkit's user community (number of downloads, active mailing list).

Our current evaluation results are found below. The information was collected by us from the websites of the toolkits or was sent to us by the developers of the toolkits. Thanks a lot to all toolkit developers and users who helped to create this guide.

Request for Support

We are trying to keep this guide up-to-date. So:

• If you know about a toolkit that we have missed, it would be nice if you could send us a link. We didn't find toolkits for ActionScript and ColdFusion yet. Is there any Semantic Web support for these languages?
• If you are a developer of one of the evaluated toolkits, it would be nice if you would have a quick look at our results and tell us if we got something wrong.
• If you are a developer of one of the toolkits and you release a new version with additional features, please let us know so that we can update our data.

All hints are highly appreciated. Please send feedback to: chris@bizer.de

Alternative Toolkit Lists

Other, alternative toolkit lists are found at

• http://esw.w3.org/topic/SemanticWebTools and
• http://www.mkbergman.com/?p=291 and
• http://planetrdf.com/guide/ and
• http://www.sekt-project.com/resources/sekt_components.html
  

2. Toolkit Comparison

This chapter lists all known toolkits ordered by programming language.
The comparison criteria are explained at the end of this document.

2.1 C

2.2 Haskell

2.3 JAVA

2.4 JavaScript

2.5 Common Lisp

2.6 .Net/Mono

2.7 PERL

2.8 PHP

2.9 Pike

2.10 Prolog

2.11 Python

2.12 Ruby

2.13 Proprietary Languages

2.14 Commercial Toolkits

3. Comparison Criteria

Latest Release

Publication date of the current release of the toolkit. If you know about a new release of any toolkit with new features, please let us know.

Number of Developers

Number of persons involved in developing and maintaining the toolkit. If the toolkit is hosted on Sourceforge, we took the number of developers listed there. Otherwise we counted everybody mentioned as developers on the project website. This figure might be misleading if a project consists of many developers who only contribute occationally.

Downloads

Total number of downloads until January 2005. If the toolkit is hosted on Sourceforge, we took the download figure listed there. If the toolkit is part of another toolkit for a different purpose (like a general XML toolkit), then we didn't use the download figure, because it doesn't reflect the demand for the actual Semantic Web toolkit. If a tool kit consists of several packages which have to be downloaded separately, we also didn't use this download figure.

Active Mailing-List

Indicator if the project has an active support mailing list. We counted a mailing-list as active if there were more than ten posts in the last three months.

License

License under which the toolkit is distributed.

API-Paradigm

This criteria describes which general API-Paradigms are offered for manipulating RDF data.

• Dataset- or Named Graphs-centric APIs allow you to represent and query RDF datasets.
• A model-centric API only allows you to load, save and delete whole RDF models.
• Through a statement-centric API, RDF data is manipulated as a set of RDF triples each consisting of a subject, predicate, and object. Usual methods are model.addStatement() or find(S,P,O).
• A resource-centric API presents a RDF model as resources having properties. Usual methods are resource.addProperty() or model.listResources().
• The ontology-centric view is an extension to the resource-centric-view by adding direct support for the kinds of objects expected to be in an ontology: classes (in a class hierarchy), properties (in a property hierarchy) and individuals. An ontology-centric API might offer methods to list its super- and sub-classes or instances of a class.

Query-Languages

List of all RDF query languages supported by the toolkit. A comparison of different Semantic Web query languages is found here. Support for SPARQL means that the toolkit supports at least some features of the standard RDF query language currently developed by DAWG.

Model Storage

List of stoage alternatives for RDF data. Possible values are

• Memory, if data is only stored in memory and has to be serialized to XML/RDF or N3 for persistence.
• DB, if the toolkit supports storing data in a standard relational or object-relational database.
• File, if the toolkit stores data in its own proprietary file format.

A scalability report on triple store applications has been published by the MIT Simile Project. The SWAD-Europe has also published a report about Open Source RDF storage systems.

Supported Databases

List of supported databases or name of the database abstraction layer used.

Supported Serialization Formats

Supported serialization formats for reading and writing RDF models. An overview about different RDF serialization formats is found here. Information about GRDDL is found here. A comparison how different toolkits handle the W3C RDF Test Cases is found here.

Reasoning Support

Ontology-languages supported by the toolkit to infer implicit statements. A language is already listed if most of the inference rules of the language are supported by the toolkit. A comparison how different toolkits handle the W3C OWL Test Cases is found here.

RDF Server

Indicator if the toolkit contains some kind of RDF server, which allows models to be queried over the web using HTTP or SOAP. For more information about RDF servers and data access protocols see W3C DAWG work on protocols.

Other Features

Additional features of the toolkit that aren't captured by other criteria.

Comments

Further comments on the toolkit.

4. Change Log

• 2007-10-25: Added LinqToRDF
• 2007-02-14: Added IBM Boca
• 2007-01-17: Added new libraries that implement linked data (Semtic Web Client Library, AJAR, SemWeb Prolog).
• 2006-11-15: Updated with information from Bansard.
• 2006-10-10: Updated NG4J to version 0.5
• 2006-06-28: Added section Commercial Toolkits and updated entry on Oracle.
• 2006-06-15: Updated entry on Sesame 2.0
• 2006-06-06: Added AJAX libraries, updated descriptions of toolkits for scripting languages.
• 2006-04-25: Updated RDF Gateway.
• 2006-03-30: Added ActiveRDF. Updated description of Redland, ARC, Jibbering and the version numbers of some more toolkits.
• 2006-01-22: Updated description of RAP, RDFLib, Redland
• 2005-10-17: Added IBM IODT and Oracle 10g
• 2005-09-14: Added Thea-VBA, Updated Wilbur
• 2005-06-13: Added SemWeb .Net toolkit.
• 2005-06-06: Updated PerlRDF.
• 2005-05-17: Reviewed up-to-dateness of the guide and updated/added Redland, Sesame, KAON2, NG4J , SOFA, appmosphere, RDFlib.
• 2005-04-20: Added link to Jena 2.2 external contribution page.
• 2005-02-15: Added NG4J, YARS, Adenine, Fabl.
• 2005-02-14: Added CARA. Updated Carp, Pychinko, Pyrple. Removed Semitar because they didn't release anything yet.
• 2005-02-11: Added Rdf Gateway. Updated Rena, RubyRdf, Samizdat, Pychinko, F-OWL, OWLJessKB, Jibbering
  rdf-parser.
• 2005-02-09: Added Metalog, SemPlan.RdfLib, Euler, EulerSharp, EulerMoz. Updated Wilbur, RdfStore.
• 2005-02-08: Updated with feedback from Andy Seaborne about Jena.
• 2005-02-08: Updated with feedback from Libby Miller about Ruby and JavaScript.
• 2005-02-08: Updated with feedback from James Carlyle about .net/MONO.
• 2005-02-08: Updated with feedback from Jos De Roo about EulerMoz and EulerSharp.
• 2005-02-04: Initial version of this document.