Hi Andy,
with your example I can extract the triples but I can’t extract the
sub-queries. Is there a simple way to extract the sub-queries from a query
pattern?
Miguel
On 08 Aug 2014, at 21:10, Andy Seaborne <a...@apache.org> wrote:
> On 08/08/14 10:15, Miguel Bento Alves wrote:
>> Hi all,
>>
>> In a Sparql query, we can extract the query pattern ( q.getQueryPattern() ).
>> For instance, in the sparql command:
>> Select ?x ?p ?z where {?x ?p ?y . ?x <eg:p> ?z.}
>> we can extract:
>> { ?x ?p ?y .
>> ?x <eg:p> ?z
>> }
>>
>> Is there anyway to extract as TriplePattern?
>
> If you are working with the parsed object, you have to test/cast the query
> pattern:
>
> Query query = QueryFactory.create("SELECT*{?s ?p ?o}") ;
> ElementGroup el = (ElementGroup)query.getQueryPattern() ;
> Element bgp = el.getElements().get(0) ;
>
> ElementPathBlock elp = (ElementPathBlock)bgp ;
> PathBlock pb = elp.getPattern() ;
> for ( TriplePath tp : pb ) {
> Triple t = tp.asTriple() ;
> if ( t == null )
> System.err.println("Path: "+tp.getPath()) ;
> else
> System.out.println(t) ;
> }
>
> Note in the syntax, you can have paths: { ?x :p/:q ?y }
>
> It is much easier to work with algebra.
>
> Op op = Algebra.compile(query.getQueryPattern()) ;
> System.out.println(op) ;
> OpBGP x = (OpBGP)op ;
> for ( Triple t : x.getPattern() ) {
> System.out.println("Algebra: -- "+t) ;
> }
>
>
>>
>> Also, we can extract the vars ( PatternVars.vars(qf.getQueryPattern()) ).
>> Is it possible to extract the the non-vars?
>
> There's no code written - you can take a copy of the the code behind
> PatternVars and modify that.
>
>>
>>
>> Miguel
>>
>
