I am pleased to offer, for your consideration, the following proposal to
accept Jena, a semantic web framework into the incubator. The text of the
proposal is copied here for your convenience and can be found at
http://wiki.apache.org/incubator/JenaProposal
We currently have two mentors so we're looking for at least one more.
Note that there is already an overlapping discussion about interaction
between this and other semantic web projects in the incubator. As champion
of this proposal I have recommended that the Jena team participate in this
discussion. I'm not able to speak for the Jena committers, but I am keen to
see *appropriate* sharing of code between projects.
However, I don't believe that this should be forced upon the three projects
as part of their incubation. Such collaboration should emerge through
community engagement, with mentor guidance, rather than through incubator
conditions of entry or graduation.
Comments and volunteers welcome.
Now for the proposal:
= Jena, a Semantic Web Framework =
== Abstract ==
Jena is a semantic web framework for Java, based on W3C standards.
== Proposal ==
Jena provides a semantic web framework in Java that implements the key W3C
recommendations for the core semantic web technologies of RDF and SPARQL.
Jena is a number of components and modules built on this core system. It
currently includes:
* an API for working with RDF
* Parsers and writers for the RDF formats (RDF/XML, Turtle, N-triples,
NQuads, TriG)
* an implementation of SPARQL, the W3C standard RDF query language
* multiple storage systems for RDF data including in-memory, file-backed,
in SQL databases and in custom scalable storage systems
* an API for manipulation of OWL
* a rule-based inference engine
* an implementation of GRDDL for extraction of RDF from XML formats
* a standards compliant IRI library.
The project includes facilities based around this core to encourage the
creation of components and contributions both as part of Jena and also as
companion open source activities.
This proposal includes the main components of Jena: the main Jena download,
ARQ, GRDDL, SDB, TDB, the IRI library and Joseki. Other components may be
contributed later - we're just starting with the main part of Jena for now.
== Background ==
The W3C recommendations provide detailed specifications and it is important
to follow these standards so that independently built applications can
exchange data over the web. Jena provides high quality Java
implementations of RDF input/output and storage so that application writers
can concentrate on the application, not the low-level details.
W3C Semantic Web: http://www.w3.org/standards/semanticweb/
Jena has been on !SourceForge since 2001.
http://sourceforge.net/projects/jena/
== Rationale ==
The open source project was originally created as part of a research
activity in HPLabs. In building new systems, the researchers identified
the value of a common platform that dealt with the low level details of
the standards. This lead to engagement with the standards process and the
creation of a framework that provided a library to deal with the details of
semantic web standards. This work was released as Jena. The developers
have contributed implementation experience back to the working groups.
None of the contributors now work for HP. Providing a uniform contributor
and licensing framework assists commercial use of Jena.
== Current Status ==
Jena is already an established project with a large user base in industry
and academia. It currently uses a BSD-style three-clause license with a
number of contributing copyright holders. Support is primarily provided via
the jena-...@groups.yahoo.com mailing list. The majority of the team was
employed in HPLabs, and HP holds the majority of the copyright over the code
- there are contributions from non-HP companies. HP decided to close the
research group as of October 2009 and the people from HPLabs connected with
the project have moved on to several different semantic web companies.
This change does not immediately affect Jena because the people who were in
HP still remain active contributors to Jena. The project continues to be
supported and actively enhanced. There is now the opportunity to become an
open source project without a single large organisation involved.
=== Meritocracy ===
The Jena team has always been self-determining; there has not been a project
manager in charge of the effort. Instead, it has grown through individuals
contributing to the codebase as part of their research activities. The team
has organised itself to create the framework for builds, releases and public
support, and people who had worked on Jena in HP, and moved to other
companies and institutions, have continued to contribute.
=== Core developers ===
Jena originated within a research activity in HPLabs, starting around 2000.
Contributors to jena have been active in W3C working groups including
chairing the "RDF Core" working group and acting as document editors on
several other working groups. W3C processes are public; jena contributors
have been involved in public debate and decision making. People have since
moved on from HP to several semantic web forced companies and to university
positions.
=== Alignment ===
Jena is already in use in many commercial systems as well as widely used in
academic research and teaching. We want to continue making this easy and
at the same time encourage contribution in a well-known environment.
Jena is already pretty much run in a collaborative open development style
with communication on mailing lists.
== Known Risks ==
=== Orphaned products& Reliance on Salaried Developers ===
Jena is in use by companies we work for so the companies have an interest in
its continued vitality.
The Jena team members are not employed to work on Jena specifically; while
there is some development as part of their day-jobs, the team members do
also contribute personal time as well.
=== Inexperience with Open Source ===
While Jena has been open-source since 2001, the majority of individuals
involved do not have wide experience of contributing to other open source
projects, so the team members need to develop more skills in participating
in open-source communities.
=== Relationships with Other Apache Products ===
Jena uses Xerces, Lucene, Apache Commons HttpClient and Apache Commons
FileUpload.
Jena is used by Clerezza (in incubation).
=== A Excessive Fascination with the Apache Brand ===
Jena has an established community of users and is used in both academic and
commercial settings. The Apache environment offers Jena the opportunity to
expand the ways that more people can be involved and contribute, and hence
to ensure the project is not dependent on the current members. We hope that
association with Apache will also encourage other open source projects that
use Jena to help develop a healthy and vibrant semantic web open source
ecosystem.
Apache offers us a clear licensing framework and support infrastructure
which would reassure the many users of Jena who exploit it in commercial
environments as well as those in other open source projects.
== Documentation ==
Overview documentation, tutorials, topic-based how-tos and detailed !JavaDoc
can be found at http://openjena.org/
== Initial Source ==
The majority of the current codebase resides in the Jena project CVS/SVN on
!SourceForge. Joseki is also on !SourceForge; we later decided to put all
projects under one SF project so this is a historical anomaly. The modules
in the initial source are:
* [[http://jena.cvs.sourceforge.net/viewvc/jena/|Jena CVS area on
SourceForge]]
* jena2 (the core system, include RDF, rules and OWL subsystems)
* iri (the IRI library)
* Eyeball and !EyeballAcceptance (a checker for RDF)
* [[http://jena.svn.sourceforge.net/viewvc/jena/|Jena SVN area on
SourceForge]]
* ARQ (SPARQL query and update engine)
* Fuseki (SPARQL server)
* grddl (GRDDL implementation for Jena)
* SDB (SQL database layer for Jena)
* TDB (customer storage layer for Jena)
* Ymris (experimental rules engine)
* Experimental/Jena3 (experiment reorganisation of jena)
* [[http://joseki.cvs.sourceforge.net/viewvc/joseki/Joseki3/|Joseki CVS
area on SourceForge]]
* Joseki3 module.
== Source and Intellectual Property Submission Plan ==
We are in discussions with HP, the largest copyright holder, about licensing
to Apache and currently HP has indicated that it is willing to do so in
principle.
== External Dependencies ==
Details of license of components used by Jena are available at:
http://openjena.org/Licenses/index.html
The Jena GRDDL Reader has some additional dependencies:
http://jena.sourceforge.net/grddl/license.html
We are heavily dependent on Xerces for both parsing and also for XML
datatype support.
== Cryptography ==
No specific cryptography.
== Required Resources ==
Mailing lists
* jena-private (with moderated subscriptions)
* jena-dev
* jena-commits
* jena-user
Subversion Directory
* jena
Issue Tracking
* JIRA
Other Resources
* Hudson
== Initial Committers ==
The intial committers are the currently active developers for Jena.
* Chris Dollin
* Paolo Castagna
* Damian Steer
* Jeremy Carroll
* Ian Dickinson
* Dave Reynolds
* Andy Seaborne
== Affiliations ==
* Epimorphics Ltd: Dave Reynolds, Ian Dickinson, Chris Dollin, Andy
Seaborne
* Talis Systems Ltd: Paolo Castagna
* University of Bristol: Damian Steer
* Top``Quadrant Inc: Jeremy Carroll
== Sponsors ==
=== Champion ===
Ross Gardler (rgardler .at. apache.org
=== Nominated Mentors ===
* Bertrand Delacretaz bdelacretaz .at. apache.org
* Leo Simons leosimons .at. apache.org
=== Sponsoring Entity ===
Incubator PMC
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