Link Resource Definition

A link is a resource which describes some relationship amongst other resources. We focus here on binary relationships - those involving exactly two resources, oftern referred to as "source" and "target". The source and target can be related in many different ways, for example, a requirement resource might be linked to a test case resource; a requirement might be linked to a change request resource. These links are have a different purpose (they are used in different ways, for instance). The nature of the relationship is captured by the "type" of the link. The type is essentially a name which describes the semantics of the link.

A link is represented by an RDF resource with type "oslc_rm:Link" having properties which describe the source, target and type of the link. Collections of links have a different media type but are simply aggregations of individual link resources.

Namespaces

• rdf - RDF XML namespace - http://www.w3.org/1999/02/22-rdf-syntax-ns#
• dc - Dublin Core Metadata Initiative (DCMI) properties namespace URI - http://purl.org/dc/terms/
• oslc_rm - OSLC RM XML namespace - http://open-services.net/xmlns/rm/1.0/
• oslc - OSLC Commons XML namespace - http://open-services.net/xmlns/common/1.0/
• foaf - http://xmlns.com/foaf/0.1/

The source, target and type of a link are described by the URIs of those resources using an RDF resource of type "oslc:Link" having the properties described in the table below.

The media type used for this RDF/XML representation MUST be application/x-oslc-common-link+xml.

The following properties are defined on an OSLC RM link resource:

Example

In this example the link resource describes an "implementedBy" relation between a workitem (which is the target of the link) and a requirement (the source).

GET http://www.example.com/resources/links/link1
Accept: application/x-oslc-common-link+xml

<?xml version="1.0" encoding="UTF-8"?>
<rdf:RDF
   xmlns:oslc="http://open-services.net/xmlns/common/1.0/"
   xmlns:dc="http://purl.org/dc/terms/"
   xmlns:foaf="http://xmlns.com/foaf/0.1/"
   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
   <oslc:Link rdf:about="http://www.example.com/resources/links/link1">
     <rdf:subject rdf:resource="http://www.example.com/resources/requirement55"/>
     <rdf:object rdf:resource="http://www.example.com/resources/workitem24"/>
     <rdf:predicate rdf:resource="http://www.example.com/types/implementedBy"/>
     <dc:created rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">
         2009-10-20T19:49:47-04:00
     </dc:created>
     <dc:creator>Ian Green</dc:creator>
     <dc:contributor>
          <foaf:Person>
              <foaf:name>A. N. Other</foaf:name>
              <foaf:mbox rdf:resource="mailto:another@example.com" />
              <foaf:img rdf:resource="https://example.com/users/another/photo"/>
          </foaf:Person>
     </dc:contributor>

   </oslc:Link>
</rdf:RDF>

Link Collection Resource Definition

A link collection resource describes a multiplicity (a number of) of links that are in some way related. A common usage of a link collection resource is to describe the link resources which are associated with a requirement or requirement collection. A link collection is described by a resource of rdf:type "rdf:Bag" which providers must be able to represent as an RDF/XML document having media type application/x-oslc-common-link-collection+xml. A link collection is an rdf:Bag containing the inlined representation of link in that collection. The special case of a link collection which does not contain any links is represented as rdf:Bag that does not contain any <rdf:li> properties.

The following table describes the RDF properties whose meaning is defined by this specification:

The representation of a link collection is the aggregation of the representations of each of the links in that collection.

Example

This example shows the two links that are associated with a resource "requirement55".

GET http://example.com/requirements/24/links
Accept: application/x-oslc-common-link-collection+xml

<?xml version="1.0" encoding="UTF-8"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
    xmlns:rm="http://open-services.net/xmlns/rm/1.0/"
    xmlns:oslc="http://open-services.net/xmlns/common/1.0/"
    xmlns:dc="http://purl.org/dc/terms/">      

   <rdf:Bag rdf:about="http://example.com/requirements/24/links">
   <rdf:li>
    <oslc:Link rdf:about="http://www.example.com/resources/links/link1">
     <rdf:subject rdf:resource="http://www.example.com/resources/requirement55"/>
     <rdf:object rdf:resource="http://www.example.com/resources/workitem24"/>
     <rdf:predicate rdf:resource="http://www.example.com/types/implementedBy"/>
     <dc:modified>29 August 2009</dc:modified>
     <dc:creator>Ian Green</dc:creator>
    </oslc:Link>
   </rdf:li>

   <rdf:li>
    <oslc:Link rdf:about="http://www.example.com/resources/links/link2">
     <rdf:subject rdf:resource="http://www.example.com/resources/requirement1"/>
     <rdf:object rdf:resource="http://www.example.com/resources/requirement55"/>
     <rdf:predicate rdf:resource="http://www.example.com/types/satisfiedBy"/>
     <dc:modified>1 January 2000</dc:modified>
    </oslc:Link>
   </rdf:li>
  </rdf:Bag>
</rdf:RDF>