xOWL Infrastructure

This is the xOWL Infrastructure, a set of components for working with datasets in the semantic web and linked data world:

• Manipulate RDF and OWL2 datasets (N-Triples, N-Quads, Turtle, RDF/XML, JSON-LD, OWL/XML, Functional OWL)
• Query engine with RDF and OWL2 interfaces
• Rule engine with RDF and OWL2 interfaces
• Expression and execution of arbitrary behavior in data using Clojure
• Deployable triple store server

xOWL is also the name of the language used to express behavior within OWL2 ontologies. xOWL basically enable the inclusion of snippets of Clojure code as named entities in ontologies. In OWL2 ontologies, an entity can be attributed several interpretations: as a class, as an individual (instance), as an object or data property, etc. With the xOWL extension, an entity can have a new behavioral interpretation defined in a piece of Clojure code:

Prefix(xsd: = <http://www.w3.org/2001/XMLSchema#>)
Prefix( : = <http://xowl.org/infra/engine/tests/Sample#>)
Ontology( <http://xowl.org/infra/engine/tests/Sample>
    FunctionDefinition(:hello (fn [] "Hello World"))
    DataPropertyAssertion(:hasName :hello "A function that says hello.")
)

How do I use this software?

As Java libraries

The xOWL Infrastructure can be used as embeddable Java libraries. With Maven, most features can be included with:

<dependency>
    <groupId>org.xowl.infra</groupId>
    <artifactId>xowl-store</artifactId>
    <version>2.1.0-SNAPSHOT</version>
    <scope>compile</scope>
</dependency>

For the inclusion of the expression and execution of behavior in ontologies, also include the xowl-engine bundle:

#!xml
<artifactId>xowl-engine</artifactId>

All libraries in the xOWL Infrastructure and their dependencies are OSGi bundles that can be readily deployed on OSGi platforms such as Apache Felix, or Eclipse Equinox.

Triple Store Server

The xOWL Infrastructure also implements a triple store server that can be used through the downloadable distribution or by using the Docker image.

To use the downloadable distribution (Java 8 required), simply download it. Then to administer the server, use the provided admin.sh script:

# Launch the server
$ ./admin.sh start
# Stop the server
$ ./admin.sh stop

With a web-browser, go to https://localhost:3443/web/. The default administrator login and password are admin and admin.

To install the xOWL triple store server as a linux daemon, simply run (sudo will be asked for):

$ ./install-daemon.sh

Then, the daemon can be controlled as usual:

$ sudo service xowl-server start
$ sudo service xowl-server stop
$ sudo service xowl-server restart

The triple store server is also available as a Docker image at nexus.cenotelie.fr/xowl/xowl-server:latest. To run the latest image:

$ docker run -d -p 3443:3443/tcp --name my-xowl-instance -v /path/to/host/data:/xowl-data nexus.cenotelie.fr/xowl/xowl-server:latest

Replace the /path/to/host/data to a path where to store the databases on your system. With a web-browser, go to https://localhost:3443/web/. The default administrator login and password are admin and admin.

How to build

To build the artifacts in this repository using Maven:

$ mvn clean install -Dgpg.skip=true

Then, to build the other redistributable artifacts (redistributable package and Docker image):

$ ./.releng/build.sh

For this, Docker must be locally installed.

How can I contribute?

The simplest way to contribute is to:

• Fork this repository on Bitbucket.
• Fix some issue or implement a new feature.
• Create a pull request on Bitbucket.

Patches can also be submitted by email, or through the issue management system.

The isse tracker may contain tickets that are accessible to newcomers. Look for tickets with [beginner] in the title. These tickets are good ways to become more familiar with the project and the codebase.

License

This software is licenced under the Lesser General Public License (LGPL) v3. Refers to the LICENSE.txt file at the root of the repository for the full text, or to the online version.