Thank you for your reply. Actually the problem is not really about the representation - for example I might use the DataCube vocabulary - but is more about how to use the Jena serialisers to stream custom triples adapted from a ResultSet efficiently. The ResultSetFormatter.toModel approach is not the one I like, as it requires the RDF to be generated in memory before serialisation. I posted my solution to SO: http://stackoverflow.com/questions/33136916/streaming-a-resultset-as-rdf-using-a-custom-vocabulary/33153024#33153024 <http://stackoverflow.com/questions/33136916/streaming-a-resultset-as-rdf-using-a-custom-vocabulary/33153024#33153024> (Are there better ways of doing that?)
However, it looks like the streaming features do not support all RDF syntax, as I got a RIOT exception when I ask for RDF/XML or RDF/JSON formats. So now my problem is how to support all serialisations. Or maybe my version of Jena is outdated (2.12.1) and I should use Jena 3? Thanks, Enrico > On 14 Oct 2015, at 18:53, A. Soroka <[email protected]> wrote: > > Perhaps you could say more about the representation you want to use? > ResultSetFormatter does feature methods that (to my understanding) do stream > using Jena serialization: > > https://jena.apache.org/documentation/javadoc/arq/org/apache/jena/query/ResultSetFormatter.html#output-java.io.OutputStream-org.apache.jena.query.ResultSet-org.apache.jena.sparql.resultset.ResultsFormat- > > <https://jena.apache.org/documentation/javadoc/arq/org/apache/jena/query/ResultSetFormatter.html#output-java.io.OutputStream-org.apache.jena.query.ResultSet-org.apache.jena.sparql.resultset.ResultsFormat-> > > --- > A. Soroka > The University of Virginia Library > >> On Oct 14, 2015, at 6:39 PM, Enrico Daga (enridaga) <[email protected] >> <mailto:[email protected]>> wrote: >> >> Hi, >> >> in my use case I need to stream a ResultSet obtained from a query to a >> remote endpoint converted into an RDF output format. >> I know Jena provides a ResultSetFormatter.toModel facility for that, however >> I have the following constraints: >> - I want to use a different representation/vocabulary and not the one >> provided by Jena, and >> - I don't want to load the data in memory. In other words I don't want to >> create a Model and fill it with the ResultSet, but streaming out the triples >> while I iterate on it, to control memory consumption. >> - I still want to benefit by the Jena serializers >> >> I have seen the StreamRDF interface, but I am not very clear about how to >> use it effectively. >> What could be a correct approach in this scenario? >> >> Thank you, >> >> Enrico >> >> — >> Enrico Daga (enridaga) >> http://www.enridaga.net <http://www.enridaga.net/> <http://www.enridaga.net/ >> <http://www.enridaga.net/>> >> Il budda e’ nel parco.
