- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Tue, 3 May 2005 17:05:57 +0100
- To: "Andrea Splendiani" <andrea@pasteur.fr>, <semantic-web@w3.org>
[[There is a mailing list for Jena - jena-dev@groups.yahoo.com - that might get you answers quicker than this list.]] The return of a RDFNode from get(var) is actually a Resource (a subclass of RDFNode). You can cast to Resource after a test of instanceof - it could be a Literal. Resource has .isAnon() to test for a blank node or a resource with a URI. > Is there any way to have a unique identifier for blank nodes to use in > other queries ? (in Protégé OWL API there is). There is an Jena-internal id for blank nodes given by .getId(). In general, looking at a blank node id is a bad idea. For example, they change each time you read an RDF/XML file. > Another question: > is there a way to ask for an approximate matching of literals ? There is regular expression testing in RDQL using =~ There isn't stemming or other more text focused operations. Andy -------- Original Message -------- > From: Andrea Splendiani <> > Date: 28 April 2005 13:44 > > Hi, > I apologize if this message reached the list twice, there may be some > problem with the network here. > > I'm trying to build a tool to interactively visualize RDF graphs. > The idea is to allow the user to start from a resource/literal (or from > a graph pattern) and dynamically explore the content of an ontology/RDF > graph, basically choosing how to expand the graphs and > selecting/distinguishing namespaces (and with the ability of displaying > large graphs). > I'm using the Protégé OWL API to parse the ontology (really this > project is part of something else that may address the owl level), > generate an OntModel and use RDQL Jena support to make queries. > > When I make a query and get(Var) out of ReslutBinding, I only have a > method to string (even if I cast it to RDFNode). This gives a URI for > resources or properties, but just a representation of the pointer for > blank nodes. > Is there any way to have a unique identifier for blank nodes to use in > other queries ? (in Protégé OWL API there is). > Is there any method to know if a variable has a blank node as value ? > (I may test if it is a well formed URI...) > > Another question: > is there a way to ask for an approximate matching of literals ? > > best, > Andrea Splendiani
Received on Tuesday, 3 May 2005 16:06:17 UTC