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Lyo/LyoOSLC4J

< Lyo

Lyo OSLC4J

What is OSLC4J?

OSLC4J is a Java toolkit for building Open Services for Lifecycle Collaboration providers and consumers. It includes:

  • annotations to decorate Java objects with OSLC attributes
  • annotations to assist with resource preview UIs (compact rendering)
  • built-in support for service provider and resource shape documents
  • libraries to simplify service provider and consumer development
  • sample applications, including an OSLC Registry (catalog) application and a Change Management provider implementation
  • Tests for the sample applications to complement the Lyo OSLC Test Suite

Components

  • OSLC4J - The core component providing OSLC annotation and model support (org.eclipse.lyo.oslc4j.core / oslc4j-core)
  • Apache Jena Provider - A library to assist with serialization/de-serialization of OSLC-annotated Java objects to/from RDF XML (org.eclipse.lyo.oslc4j.core / oslc4j-jena-provider).
  • Apache Wink Json4J Provider - A library to assist with serialization/de-serialization of OSLC-annotated Java objects to/from JSON (org.eclipse.lyo.oslc4j.core / oslc4j-json4j-provider).
  • Apache Wink JAX-RS Provider - Utility classes, including an OSLC REST Client, to facilitate development using the Apache Wink JAX-RS implementation.

The Apache Jena and Apache Wink components are the built-in providers for RDF, RDF XML, JSON and JAX-RS. Additional providers could be implemented using technologies such as OpenRDF and Jersey.

Using in Maven

Be sure to add Eclipse Maven repositories in your POM file before adding OSLC4J dependencies:

<repositories>
    <repository>
        <id>lyo-releases</id>
        <name>Eclipse Lyo Releases</name>
        <url>https://repo.eclipse.org/content/repositories/lyo-releases/</url>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
    </repository>
    <repository>
        <id>lyo-snapshots</id>
        <name>Eclipse Lyo Snapshots</name>
        <url>https://repo.eclipse.org/content/repositories/lyo-snapshots/</url>
        <releases>
            <enabled>false</enabled>
        </releases>
    </repository>
</repositories>

Sample code

Annotation sample

    //sample simple string attribute (dcterms:description, as in http://open-services.net/bin/view/Main/OSLCCoreSpecAppendixA#Dublin_Core_Properties)
 
    @OslcDescription("Descriptive text (reference: Dublin Core) about resource represented as rich text in XHTML content.")
    @OslcPropertyDefinition(OslcConstants.DCTERMS_NAMESPACE + "description")
    @OslcTitle("Description")
    @OslcValueType(ValueType.XMLLiteral)
    public String getDescription()
    {
        return description;
    }  
 
    //sample relationship attribute (oslc_cm:affectsTestResult, as in http://open-services.net/bin/view/Main/CmSpecificationV2#Resource_ChangeRequest)
 
    @OslcDescription("Associated QM resource that is affected by this Change Request.")
    @OslcName("affectsTestResult")
    @OslcPropertyDefinition(Constants.CHANGE_MANAGEMENT_NAMESPACE + "affectsTestResult")
    @OslcRange(Constants.TYPE_TEST_RESULT)
    @OslcReadOnly(false)
    @OslcTitle("Affects Test Results")
    public URI[] getAffectsTestResults()
    {
        return affectsTestResults.toArray(new URI[affectsTestResults.size()]);
    }

JAX-RS method sample

This illustrates implementation of an OSLC-CM (REST) server/provider

    //support GET for a specific OSLC ChangeRequest
 
    @GET
    @Path("{changeRequestId}")
    @Produces({OslcMediaType.APPLICATION_RDF_XML, OslcMediaType.APPLICATION_XML, OslcMediaType.APPLICATION_JSON})
    public ChangeRequest getChangeRequest(@Context                      final HttpServletResponse httpServletResponse,
                                          @PathParam("changeRequestId") final String              changeRequestId)
    {
        final ChangeRequest changeRequest = Persistence.getChangeRequest(changeRequestId);
        if (changeRequest != null)
        {
            changeRequest.setServiceProvider(ServiceProviderSingleton.getServiceProviderURI());
            setETagHeader(getETagFromChangeRequest(changeRequest), httpServletResponse);
            return changeRequest;
        }
        throw new WebApplicationException(Status.NOT_FOUND);
    }
 
    //support POST to create a new ChangeRequest
 
    @POST
    @Consumes({OslcMediaType.APPLICATION_RDF_XML, OslcMediaType.APPLICATION_XML, OslcMediaType.APPLICATION_JSON})
    @Produces({OslcMediaType.APPLICATION_RDF_XML, OslcMediaType.APPLICATION_XML, OslcMediaType.APPLICATION_JSON})
    public Response addChangeRequest(@Context final HttpServletRequest  httpServletRequest,
    		                         @Context final HttpServletResponse httpServletResponse,
                                              final ChangeRequest       changeRequest)
           throws URISyntaxException
    {
        final long identifier = Persistence.getNextIdentifier();
        final URI about = new URI(httpServletRequest.getScheme(),
                                  null,
                                  httpServletRequest.getServerName(),
                                  httpServletRequest.getServerPort(),
                                  httpServletRequest.getContextPath() + "/changeRequests/" + identifier,
                                  null,
                                  null);
        changeRequest.setAbout(about);
        changeRequest.setIdentifier(String.valueOf(identifier));
        changeRequest.setServiceProvider(ServiceProviderSingleton.getServiceProviderURI());
 
        final Date date = new Date();
 
        changeRequest.setCreated(date);
        changeRequest.setModified(date);
 
        Persistence.addChangeRequest(changeRequest);
        setETagHeader(getETagFromChangeRequest(changeRequest), httpServletResponse);
 
        return Response.created(about).entity(changeRequest).build();
    }

Getting started with OSLC4J

See Setting up OSLC4J for information on setting up a development environment and building the OSLC4J code samples.


JARs are no longer available for download since Lyo 2.1.0. All artefacts are available through Eclipse Maven repos linked above. Lyo Designer is available through an Eclipse download site.

See also

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