Re: Jena Fuseki named graph issue

[Andy Seaborne]

On 06/03/16 18:30, Valerio Belcastro wrote:
Do I need to get the entire default graph each time I need prefixes? Isn't
this low-performant when dealing with big default graphs?

Not if the graph is empty :-)

But any graph-based query will return the prefixes regardless of results 
so for example:

CONSTRUCT {} WHERE {FILTER(false) }

or

CONSTRUCT WHERE {}

        Andy


2016-03-06 17:41 GMT+01:00 Andy Seaborne <a...@apache.org>:

The prefixes for serialization are taken from the default graph.

You can load the default graph just with prefixes, and no triples, to
control the output from a named graph.

     Andy


On 05/03/16 11:57, Valerio Belcastro wrote:

Hi guys,

I launched Fuseki 2.3.1 as a standalone server on my local machine from
command line like this:

path-to-fuseki-folder>fuseki-server --update --mem /myData

Then I uploaded some data into the dataset default graph using this code
snippet:

     String personURI    = "http://somewhere/JohnSmith";;
     String malcolmURI   = "http://somewhere/MalcolmGraves";;
     String givenName    = "John";
     String familyName   = "Smith";
     String fullName     = givenName + " " + familyName;
     String fullName2    = "Malcolm Graves";
     String email        = givenName+familyName+"@gmail.com";
            // create an empty Model
     Model model = ModelFactory.createDefaultModel();
     // create the resource   //   and add the properties cascading style
     Resource johnSmith
         = model.createResource(personURI)
             .addProperty(VCARD.FN, fullName)
            .addProperty(VCARD.N,
                model.createResource()
                   .addProperty(VCARD.Given, givenName)
                   .addProperty(VCARD.Family, familyName));

     model.setNsPrefix("vcard", VCARD.getURI());
     DatasetAccessor dsa = DatasetAccessorFactory.createHTTP("http:/
/localhost:3030/myData/data");

     dsa.add(model);


After that, I retrieved the default graph and printed his prefix map:

     Iterator<Map.Entry<String, String>> nsIt = dsga.getModel().getN
sPrefixMap().entrySet().iterator();
     nsIt.forEachRemaining(ns -> {
       System.out.println(ns);   });


The output I obtained is the following:

     vcard=http://www.w3.org/2001/vcard-rdf/3.0#

     rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns#


If I do the same thing loading the model into a named graph instead of
the defaultgraph nothing is printed on console, it is like the prefix
map is empty.

Do I need to configure something to make things work?

Thank you in advance