[jira] [Commented] (JENA-1031) Aliases for data properties not used

["Andy Seaborne (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JENA-1031?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14876058#comment-14876058 ] 

Andy Seaborne commented on JENA-1031:
-------------------------------------

I'm not seeing quite the same thing as you (strictly this is with Jena development master):

The models are not isomorphic because "3.0e1" becomes  "3.0E1". 
Changing {{test.ttl}} from {{3.0e1}} to {{3.0E1}} and they are isomorphic.

Jena uses [jsonld-java|https://github.com/jsonld-java/] for JSON-LD support. 

It looks like it is the way jsonld-java is round-tripping numbers.
And some JSON-LD does not round trip because of JSON "interesting" treatment of numbers.

{code}
    public void jenaBugTest() throws IOException {
        Model model =  RDFDataMgr.loadModel("/home/afs/tmp/test.ttl") ;
        StringWriter writer = new StringWriter();
        RDFDataMgr.write(writer, model, RDFLanguages.JSONLD);
        writer.close();
        Model model2 = ModelFactory.createDefaultModel();
        model2.read(new StringReader(writer.toString()), "http://example.com", RDFLanguages.strLangJSONLD);

        System.out.println("----JSONLD model:");
        RDFDataMgr.write(System.out, model, RDFLanguages.JSONLD);
        System.out.println("----JSONLD model2:"); 
        RDFDataMgr.write(System.out, model, RDFLanguages.JSONLD);
        System.out.println("----Turtle model:") ; 
        RDFDataMgr.write(System.out, model, RDFLanguages.TTL);
        System.out.println("----Turtle model2:") ; 
        RDFDataMgr.write(System.out, model2, RDFLanguages.TTL);
        System.out.println("---------"); 
        System.out.println("Isomorphic? "+model.isIsomorphicWith(model2)) ;
    }
{code}

{code}
----JSONLD model:
{
  "@id" : "file:///home/afs/tmp/a",
  "http://example.com/ontology#doubleValuedProperty" : 30.0,
  "http://www.w3.org/2000/01/rdf-schema#label" : "b",
  "@context" : {
    "doubleValuedProperty" : {
      "@id" : "http://example.com/ontology#doubleValuedProperty",
      "@type" : "http://www.w3.org/2001/XMLSchema#double"
    },
    "label" : {
      "@id" : "http://www.w3.org/2000/01/rdf-schema#label",
      "@type" : "http://www.w3.org/2001/XMLSchema#string"
    }
  }
}
----JSONLD model2:
{
  "@id" : "file:///home/afs/tmp/a",
  "http://example.com/ontology#doubleValuedProperty" : 30.0,
  "http://www.w3.org/2000/01/rdf-schema#label" : "b",
  "@context" : {
    "doubleValuedProperty" : {
      "@id" : "http://example.com/ontology#doubleValuedProperty",
      "@type" : "http://www.w3.org/2001/XMLSchema#double"
    },
    "label" : {
      "@id" : "http://www.w3.org/2000/01/rdf-schema#label",
      "@type" : "http://www.w3.org/2001/XMLSchema#string"
    }
  }
}
----Turtle model:
<file:///home/afs/tmp/a>
        <http://www.w3.org/2000/01/rdf-schema#label>
                "b" ;
        <http://example.com/ontology#doubleValuedProperty>
                3.0e1 .
----Turtle model2:
<file:///home/afs/tmp/a>
        <http://www.w3.org/2000/01/rdf-schema#label>
                "b" ;
        <http://example.com/ontology#doubleValuedProperty>
                3.0E1 .
---------
Isomorphic? false
{code}


> Aliases for data properties not used
> ------------------------------------
>
>                 Key: JENA-1031
>                 URL: https://issues.apache.org/jira/browse/JENA-1031
>             Project: Apache Jena
>          Issue Type: Bug
>          Components: Jena
>    Affects Versions: Jena 3.0.0
>         Environment: Ubuntu 14.04 64bit, IntelliJ IDEA, JDK 8
>            Reporter: Gert van Valkenhoef
>            Priority: Minor
>
> When JSON-LD is generated for a graph, the @context will contain property aliases for all properties used in the graph. However, for properties that have a data value (rather than a resource), these aliases are not used, and the properties in the @graph are still their full URIs. This is harmful when the @context also specifies a data type. For example, doubles can be converted to integer by accident. The example turtle below results in JSON-LD that when parsed by Jena is not isomorphic with the graph parsed from turtle (because the doubleValuedProperty will get an integer value):
> {code:title=test.ttl}
> <a> <http://www.w3.org/2000/01/rdf-schema#label> "b".
> <a> <http://example.com/ontology#doubleValuedProperty> 3.0e1 .
> {code}
> The JSON-LD as output by Jena:
> {code:javascript}
> {
>   "@id" : "http://example.com/a",
>   "http://example.com/ontology#doubleValuedProperty" : 30.0,
>   "http://www.w3.org/2000/01/rdf-schema#label" : "b",
>   "@context" : {
>     "doubleValuedProperty" : {
>       "@id" : "http://example.com/ontology#doubleValuedProperty",
>       "@type" : "http://www.w3.org/2001/XMLSchema#double"
>     },
>     "label" : {
>       "@id" : "http://www.w3.org/2000/01/rdf-schema#label",
>       "@type" : "http://www.w3.org/2001/XMLSchema#string"
>     }
>   }
> }
> {code}
> A failing unit test for round-trip through JSON-LD:
> {code:java}
>   @Test
>   public void jenaBugTest() throws IOException {
>     Model model = ModelFactory.createDefaultModel();
>     model.read(new FileReader("test.ttl"), "http://example.com", RDFLanguages.strLangTurtle);
>     StringWriter writer = new StringWriter();
>     RDFDataMgr.write(writer, model, RDFLanguages.JSONLD);
>     writer.close();
>     System.out.println(writer.toString());
>     Model model2 = ModelFactory.createDefaultModel();
>     model2.read(new StringReader(writer.toString()), "http://example.com", RDFLanguages.strLangJSONLD);
>     assertTrue(model.isIsomorphicWith(model2));
>   }
> {code}



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