Description

umbreak

opened on Sep 27, 2018

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This is a simplified version of the problem I'm facing.

Having the following json A:

{
  "@context": {
    "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  },
  "@id": "http://example.com/main/id",
  "rdf:type": {
    "@id": "http://example.com/rdf/id",
    "rdf:label": "someLabel"
  }
}

And the following framing B:

{
  "@context" : {
    "rdf" : "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  },
  "@id" : "http://example.com/main/id"
}

And here is the code I am using to make the apply the framing (it is in Scala, but the conversion to Java should be Trivial).

   // the original Json (A) converted to a Jena Model
   val jsonModel: Model = ???
   // the context of the original Json (A)
   val contextJson: String = ???
   // the framing (B)
   val frame: String = ???

    val g   = DatasetFactory.wrap(jsonModel).asDatasetGraph
    val out = new ByteArrayOutputStream()
    val w   = RDFDataMgr.createDatasetWriter(RDFFormat.JSONLD_FRAME_FLAT)
    val pm  = RiotLib.prefixMap(g)
    val ctx = new JsonLDWriteContext()
    ctx.setJsonLDContext(contextJson)
    ctx.setFrame(frame)
    Try {
      w.write(out, g, pm, null, ctx)
    }.flatMap(_ => parse(out.toString).toTry)

The output generated is wrong:

{
  "@context" : {
    "rdf" : "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  },
  "@graph" : [
    {
      "@id" : "http://example.com/main/id",
      "@type" : "http://example.com/rdf/id"
    }
  ]
}

...because it is omitting the label. I'm expecting the output to be as the input. That's also the behaviour in the Json-LD Playground.

More weirdly, when using a different predicate than rdf:type, the output is correct. So I guess is something related to the special way rdf:type (@type) is being treated when framing.

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1. dr0i

   added a commit that references this issue on Oct 27, 2018

   Provide test for jsonld-java#242

   47f7cb4
2. dr0i commented on Oct 27, 2018

   

   dr0i

   on Oct 27, 2018

   Member

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   @umbreak I created a test using 0.12.2-SNAPSHOT as base and your json input and frame.
   The result seems to be ok - it has the label included.
   Please have a look if I am missing something.
3. umbreak commented on Oct 27, 2018

   

   umbreak

   on Oct 27, 2018

   ContributorAuthor

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   Yes, your test works. However, the way the variable in in generated is different in your test than it is in Jena

   //Your test
   final Object in = JsonUtils.fromString(jsonString);
   //Jena
   Object in = (new JsonLdApi(opts)).fromRDF(jsonldDataset, true);

   Jena uses a RDFDataset which then is converted using jsonld-java JsonLdApi into the in variable.

   If you change this line in your test with the following:

   RDFDataset ds = new RDFDataset();
   ds.addTriple("http://example.com/main/id", "http://www.w3.org/1999/02/22-rdf-syntax-ns#type", "http://example.com/rdf/id");
   ds.addTriple("http://example.com/rdf/id", "http://www.w3.org/1999/02/22-rdf-syntax-ns#label", "someLabel", null, null);
   Object in = new JsonLdApi(opts).fromRDF(ds, true);

   It still fails.
4. umbreak commented on Nov 6, 2018

   

   umbreak

   on Nov 6, 2018

   ContributorAuthor

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   The issue is related to the logic to convert rdf:type into @type defined here.

   This can only be done in the case the @id of the rdf:type does not contain any other field. Right now the logic is doing the conversion without checking that condition.
5. ansell

   closed this as completedin #245on Nov 7, 2018
6. hmichopoulos commented on Jul 26, 2021

   

   hmichopoulos

   on Jul 26, 2021

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   @umbreak , could you please explain why we need to add the condition !nodes.containsKey(object.getValue()) ?

   The specification https://www.w3.org/TR/json-ld-api/#serialize-rdf-as-json-ld-algorithm doesn't mention such thing.
   The result is that when I am trying to convert the following from ttl to json-ld

   @prefix masterData: <http://example.com/masterData#> .
   @prefix exampleModel: <http://example.com/exampleModel#> .
   @prefix example: <http://example.com/example#> .
   @prefix owl: <http://www.w3.org/2002/07/owl#> .
   @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
   @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
   @prefix skos: <http://www.w3.org/2004/02/skos/core#> .
   
   <http://example.com/masterData>
   rdf:type owl:Ontology ;
   owl:imports <http://www.w3.org/2004/02/skos/core> ;
   owl:versionInfo "Created with TopBraid Composer" ;
   .
   
   <http://example.com/FirstClass>
   rdf:type owl:Ontology ;
   .
   
   exampleModel:FirstClass
   rdf:type owl:Class ;
   rdfs:subClassOf owl:Thing ;
   .
   
   exampleModel:FirstClass
   skos:prefLabel "Deliverable Descriptor" ;
   .
   
   example:oneTwoThree
   rdf:type exampleModel:FirstClass ;
   rdf:type exampleModel:SecondClass ;
   exampleModel:entityStatus "Deprecated" ;
   exampleModel:priority 1 ;
   skos:prefLabel "An element" ;
   .
   

   it returns

   {
     "@graph" : [ {
       "@id" : "http://example.com/FirstClass",
       "@type" : "owl:Ontology"
     }, {
       "@id" : "example:oneTwoThree",
       "@type" : "exampleModel:SecondClass",
       "entityStatus" : "Deprecated",
       "exampleModel:priority" : 1,
       "rdf:type" : {
         "@id" : "exampleModel:FirstClass"
       },
       "prefLabel" : "An element"
     }, {
       "@id" : "exampleModel:FirstClass",
       "@type" : "owl:Class",
       "subClassOf" : "owl:Thing",
       "prefLabel" : "Deliverable Descriptor"
     }, {
       "@id" : "http://example.com/masterData",
       "@type" : "owl:Ontology",
       "imports" : "http://www.w3.org/2004/02/skos/core",
       "versionInfo" : "Created with TopBraid Composer"
     } ],
     "@context" : {
       "versionInfo" : {
         "@id" : "http://www.w3.org/2002/07/owl#versionInfo"
       },
       "imports" : {
         "@id" : "http://www.w3.org/2002/07/owl#imports",
         "@type" : "@id"
       },
       "prefLabel" : {
         "@id" : "http://www.w3.org/2004/02/skos/core#prefLabel"
       },
       "subClassOf" : {
         "@id" : "http://www.w3.org/2000/01/rdf-schema#subClassOf",
         "@type" : "@id"
       },
       "priority" : {
         "@id" : "http://example.com/exampleModel#priority",
         "@type" : "http://www.w3.org/2001/XMLSchema#integer"
       },
       "entityStatus" : {
         "@id" : "http://example.com/exampleModel#entityStatus"
       },
       "masterData" : "http://example.com/masterData#",
       "owl" : "http://www.w3.org/2002/07/owl#",
       "rdf" : "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
       "skos" : "http://www.w3.org/2004/02/skos/core#",
       "rdfs" : "http://www.w3.org/2000/01/rdf-schema#",
       "exampleModel" : "http://example.com/exampleModel#",
       "example" : "http://example.com/example#"
     }
   }

   but both https://www.easyrdf.org/converter and http://rdfvalidator.mybluemix.net/ convert it in a way where both types of example:oneTwoThree are returned into @type
7. dr0i commented on Mar 4, 2022

   

   dr0i

   on Mar 4, 2022

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   Thx @hmichopoulos for your report. It has become a new issue: #329.

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