Jena tdbloader assembler

How to load TDB storage with inference via tdbloader.bat (windows, Jena 2.7.3)?

I used this assembler file:

 @prefix tdb: <http://jena.hpl.hp.com/2008/tdb#> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
 @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
 @prefix ja: <http://jena.hpl.hp.com/2005/11/Assembler#> .
 @prefix tdb: <http://jena.hpl.hp.com/2008/tdb#> .

 [] ja:loadClass "com.hp.hpl.jena.tdb.TDB" .
 tdb:DatasetTDB rdfs:subClassOf ja:RDFDataset .
 tdb:GraphTDB rdfs:subClassOf ja:Model .

  <#dataset> rdf:type ja:RDFDataset ;
          ja:defaultGraph <#infModel> .

   <#infModel>  a ja:InfModel ;
         ja:baseModel <#tdbGraph>; 
            ja:reasoner 
            [ ja:reasonerURL <http://jena.hpl.hp.com/2003/OWLFBRuleReasoner> ].

    <#tdbGraph> rdf:type tdb:GraphTDB ;
                     tdb:location "DB";
 .

My command:

c:\apache-jena-2.7.3\bat>tdbloader --tdb=test.ttl C:\apache-jena-2.7.3\Lubm10\*

I got an exception:

   java.lang.ClassCastException: com.hp.hpl.jena.reasoner.rulesys.FBRuleInfGraph cannot be cast to com.hp.hpl.jena.tdb.store.GraphTDB

What is wrong? (removing semicolon after "DB" - does not help)

Solution

It's not clear what you are trying to achieve. tdbloader is a tool for loading triples into a TDB store, prior to processing those triples via your app or SPARQL end-point. Separately, from your app code, you can construct a Jena model which uses the inference engine over a base model from a TDB graph. But I can't see why you are using an inference model at load time. If you look at the exception you are getting:

FBRuleInfGraph cannot be cast to com.hp.hpl.jena.tdb.store.GraphTDB

it confirms that you can't use an inference graph at that stage of the process, and I'm not sure why you would. Unless, of course, you are trying to statically compute the inference closure over the base model and store that in TDB, saving the need for inference computation at runtime. However, if you are trying to do that, I don't believe that can currently be done via the Jena assembler. You'll have to write custom code to do that at the moment.

Bottom line: separate the concerns. Use a plain graph description for tdbloader, use the inference graph at run time.