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ghillairet / emftriple

EMF Binding for RDF
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RDF Binding for EMF

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EMFTriple is an RDF binding for EMF that will help you persist your EMF models in RDF instead of XMI. EMFTriple can work on regular RDF files and RDF data stores such as the various Sesame implementations (SailRepository) and Jena TDB.

EMFTriple comes with two independent implementation, the first makes use of Jena, the second of Sesame. Both implementations provide basic support for reading and writing RDF files in different formats (RDF/XML, Turtle, N-Triples). The Sesame implementation can also work over any SailRepository implementations, while the Jena one can also work over the TDB store.

Installation

Current version: 1.1.0

Update Site: http://ghillairet.github.io/p2 (Composite update site with Jena and Sesame OSGI bundles. See the content from your browser.)

Getting Started

Register the desired Resource.Factory, e.g. RDFResourceFactory for generating RDF/XML files. Registering a Resource.Factory is the only thing you have to do to work with RDF. The RDFResourceFactory is implemented for both Jena and Sesame (examples/org.eclipselabs.emftriple.examples.maven.jena and examples/org.eclipselabs.emftriple.examples.maven.sesame, respectively).

Resource.Factory.Registry.INSTANCE.getExtensionToFactoryMap().put("*", new RDFResourceFactory());

Create your resources and fill it with some objects. The Book class is defined in the org.eclipselabs.emftriple.junit project.

ResourceSet resourceSet = new ResourceSetImpl();
Resource r = resourceSet.createResource(URI.createURI("http://my.rdf"));

Book b = ModelFactory.eINSTANCE.createBook();
b.setTitle("The Book");
b.getTags().add("SciFI");
b.getTags().add("Fantasy");

r.getContents().add(b);

Save it to a stream.

r.save(System.out, null);

The Jena version produces the following RDF/XML document:

<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:j.0="http://www.eclipselabs.org/emf/junit#//Book/"
    xmlns:j.1="http://www.eclipselabs.org/emf/junit#//" > 
  <rdf:Description rdf:about="http://my.rdf#/">
    <j.0:tags>Fantasy</j.0:tags>
    <j.0:tags>SciFI</j.0:tags>
    <j.0:title>The Book</j.0:title>
    <rdf:type rdf:resource="http://www.eclipselabs.org/emf/junit#//Book"/>
  </rdf:Description>
</rdf:RDF>

Resource Factories

Jena:

Sesame:

RDF Stores

When using emftriple on top of an RDF store, you need to use a specific URIHandler that will tell the EMF Resource framework how the Resource can be loaded and saved. Also in that case, a Resource will be map to an RDF named graph, with the Resource URI being the named graph URI or identifier. This will allow a clear storage of EMF models into your RDF store and make it easy to retrieve them.

Jena TDB

Initialize the TDB dataset.

Dataset dataset = TDBFactory.createDataset();

Register the RDF Resource.Factory and create a new ResourceSet.

Resource.Factory.Registry.INSTANCE.getExtensionToFactoryMap().put("*", new RDFResourceFactory());
ResourceSet resourceSet = new ResourceSetImpl();

Add to the resourceSet the URIHandler specific to TDB with the required dataset.

resourceSet.getURIConverter().getURIHandlers().add(0, new TDBHandler(dataset));

Create a resource as usual, this one will be saved or loaded from the named graph http://my.rdf in the dataset.

Resource r = resourceSet.createResource(URI.createURI("http://my.rdf"));

Sesame SailRepository

Initialize a SailRepository.

Repository repo = new SailRepository(new MemoryStore());
repo.initialize();

Register the RDF Resource.Factory and create a new ResourceSet.

Resource.Factory.Registry.INSTANCE.getExtensionToFactoryMap().put("*", new RDFResourceFactory());
ResourceSet resourceSet = new ResourceSetImpl();

Add to the resourceSet the URIHandler specific to SailRepository with the required repository.

resourceSet.getURIConverter().getURIHandlers().add(0, new RepositoryHandler(repo));

Create a resource as usual, this one will be saved or loaded from the named graph http://my.rdf in the repository.

Resource r = resourceSet.createResource(URI.createURI("http://my.rdf"));

Using from Maven

  1. Get the source code:

    git clone https://github.com/ghillairet/emftriple.git

  2. Import the root project in Eclipse using Import Maven Projects of the m2e plugin.

  3. Compile and generate update site.

    mvn clean install

  4. Add the required Maven dependencies. Note that Tycho dependencies from Maven are not transitive, so you have to explicitly add the the dependencies of EMFTriple as well.

    For Sesame:

    <dependency>
    <groupId>org.eclipselabs</groupId>
    <artifactId>org.eclipselabs.emftriple.sesame</artifactId>
    <version>1.1.0-SNAPSHOT</version>
</dependency>

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-simple</artifactId>
    <version>1.7.13</version>
</dependency>

<!-- for using a Sail Repository -->

<dependency>
    <groupId>org.openrdf.sesame</groupId>
    <artifactId>sesame-repository-sail</artifactId>
    <version>2.8.8</version>
</dependency>

    For Jena:

    <dependency>
    <groupId>org.eclipselabs</groupId>
    <artifactId>org.eclipselabs.emftriple.jena</artifactId>
    <version>1.1.0-SNAPSHOT</version>
</dependency>

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-simple</artifactId>
    <version>1.7.13</version>
</dependency>

    The example metamodel is available in the org.eclipselabs.emftriple.junit project:

    <dependency>
    <groupId>org.eclipselabs</groupId>
    <artifactId>org.eclipselabs.emftriple.junit</artifactId>
    <version>1.1.0-SNAPSHOT</version>
</dependency>

License

This software is distributed under the terms of the Eclipse Public License 1.0 - http://www.eclipse.org/legal/epl-v10.html.