[oslc-core] Using OSLC Resource Shapes

Thu Oct 27 13:04:37 EDT 2011

Hello Ian,

Thanks for the response.

Yes it is not possible to express inheritance or generalization/specialization with RDF. Our short term solution is to provide a resource structure for “each possible shape” of models. However, this is of course restricted and a poor solution.

One will face this issue in each project where the interoperability should be changed from ecore/MM to OSLC RDF. However, since there are many running projects which will adopt OSLC, this will be a common challenge in the future.

Regards,

Parham Vasaiely

From: Ian Green1 [mailto:ian.green at uk.ibm.com] 
Sent: Thursday, October 27, 2011 9:11 AM
To: Vasaiely, Parham
Cc: oslc-core at open-services.net; oslc-core-bounces at open-services.net
Subject: Re: [oslc-core] Using OSLC Resource Shapes

Hello Parham, 

The RmSpecificationV2Shapes page to which you refer is in error. I've fixed this page so that each oslc:Property has exactly one oslc:valueType, as required.  (I created an entry in the issue page at [1].) 

On your other point concerning expressing the Ecore model in RDF.  In general, this is not possible since Ecore and RDF have different expressive powers.  The additional meaning that OSLC Resource Shape brings (in addition to RDF) is not adequate either, as your example illustrates. 

best wishes,
   -ian 

[1] http://open-services.net/bin/view/Main/RmSpecificationV2Issues <http://open-services.net/bin/view/Main/RmSpecificationV2Issues> 

ian.green at uk.ibm.com (Ian Green1/UK/IBM at IBMGB)
Chief Software Architect, Requirements Definition and Management
IBM Rational 

From: 

"Vasaiely, Parham" <parham.vasaiely at eads.com> 

To: 

<oslc-core at open-services.net> 

Date: 

26/10/2011 17:17 

Subject: 

[oslc-core] Using OSLC Resource Shapes 

Sent by: 

oslc-core-bounces at open-services.net

________________________________

Hi all, 

We are trying to implement OSCL in an existing project by defining first ResourceShapes to represent an existing MetaModel (Ecore). 

We are facing now the following problem: 
1) 
By trying to specify a property for a Resource with multiple possible types (oslc:range) the ResourceShape Spec. denies the specification of multiple Shapes for the resource. However, since our property can have the type FormalAssertion and InformalAssertion it should provide different shapes. Is our statement correct? 

<oslc:Property> 
<oslc:name>weakAssumption</oslc:name> 
<oslc:propertyDefinition rdf:resource="http://www.sample.eu/rtp/2.0/CMM/OSLC/attributeDefinitions/weakAssumption <http://www.sample.eu/rtp/2.0/CMM/OSLC/attributeDefinitions/weakAssumption> " /> 
                                <dcterms:title rdf:parseType="Literal">weakAssumption</dcterms:title> 
<dcterms:description rdf:parseType="Literal">CMM.Requirements.SystemRequirement.weakAssumption</dcterms:description> 
                                <oslc:representation rdf:resource="http://open-services.net/ns/core#Reference <http://open-services.net/ns/core#Reference> " /> 
                                <oslc:valueType rdf:resource="http://open-services.net/ns/core#Resource <http://open-services.net/ns/core#Resource> " /> 
                                <oslc:valueShape rdf:resource="http://www.sample.eu/rtp/2.0/CMM/OSLC/shapes/Assertion <http://www.sample.eu/rtp/2.0/CMM/OSLC/shapes/Assertion> " /> 
                                <oslc:range rdf:resource="http://www.sample.eu/rtp/2.0/CMM/OSLC/types/FormalAssertion <http://www.sample.eu/rtp/2.0/CMM/OSLC/types/FormalAssertion> " /> 
                                <oslc:range rdf:resource="http://www.sample.eu/rtp/2.0/CMM/OSLC/types/InformalAssertion <http://www.sample.eu/rtp/2.0/CMM/OSLC/types/InformalAssertion> " /> 
                                <oslc:occurs rdf:resource="http://open-service.net/ns/core#Zero-or-many <http://open-service.net/ns/core#Zero-or-many> " /> 
</oslc:Property> 
</oslc:property> 

2) 
In the example shape provided by at http://open-services.net/bin/view/Main/RmSpecificationV2Shapes <http://open-services.net/bin/view/Main/RmSpecificationV2Shapes>  one can see that the property description has two value-types. However the shape spec. is defining that a property must have exactly one value-type. But the core also allows multiple types for a property as you can see in the part “Defining OSLC Properties: Value-types: A property MAY allow multiple value-types and a value MUST satisfy one of them…” 

Is there something we have missed in the specification? 
Can we specify a property shape like the one below? 

<oslc:property> 
                <oslc:Property> 
                                <oslc:name>description</oslc:name> 
                                <oslc:propertyDefinition rdf:resource="http://purl.org/dc/terms/description <http://purl.org/dc/terms/description> " /> 
                                <dcterms:title rdf:parseType="Literal">Description 
                                </dcterms:title> 
                                <dcterms:description rdf:parseType="Literal">CMM.NamedElement.comment</dcterms:description> 
                                <!-- Use XMLLiteral String Representation --> 
                                <oslc:valueType               rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral <http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral> " /> 
                                <!-- Zero-or-one defined by RMv2Spec --> 
                                <oslc:occurs rdf:resource="http://open-service.net/ns/core#Zero-or-many <http://open-service.net/ns/core#Zero-or-many> " /> 
                </oslc:Property> 
</oslc:property> 

Many thanks! 

Kind Regards, 
Parham Vasaiely
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