I think the problem is that in the cases where this does not apply you return the original input rather than making a copy so you overwrite some/all of your changes
Try replacing the following: return opUnion; With the following: return super.transform(opUnion, left, right); NB - I haven't tested this, but based on my experience of extending TransformCopy this is likely the culprit. Rob On 8/26/13 6:22 PM, "Diogo FC Patrao" <[email protected]> wrote: >Hi all, > >I'm having trouble figuring out how Transformer class is working. See my >classes below: > > >public class GrumpyOptimizer extends TransformCopy { > >@Override > public Op transform(OpUnion opUnion, Op left, Op right) { > if ( !( left instanceof OpService && right instanceof OpService)) > return opUnion; > Node l = ((OpService)left).getService(); >Node r = ((OpService)right).getService(); > >// both runs go inside this if > if (l.toString().compareToIgnoreCase(r.toString()) > 0 ) { >return new OpUnion( right, left ); > } >return opUnion; > } > >} > >// --- test > > GrumpyOptimizer go = new GrumpyOptimizer(); > > System.out.println("Teste 1"); > > Query query = QueryFactory.create("SELECT ?a {" + > >//** "{ SERVICE <http://3.com/> { ?a < >http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://marafo.com/teste> >} }" + > >//** "UNION " + > > "{ SERVICE <http://2.com/> { ?a < >http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://marafo.com/teste> >} }" + > > "UNION " + > > "{ SERVICE <http://1.com/> { ?a < >http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ><http://marafo.com/chatuba> >} } }" ); > > > Op op = Algebra.compile(query); > > System.out.println(op); > > op = Transformer.transform(go, op); > > System.out.println(op); > >Ok; when running the code above keeping the commented lines, I get the >expected result below: > >Teste optimizer >(project (?a) > (union > (service <http://2.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < >http://marafo.com/teste>))) > (service <http://1.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < >http://marafo.com/chatuba>))))) > >(project (?a) > (union > (service <http://1.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < >http://marafo.com/chatuba>))) > (service <http://2.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < >http://marafo.com/teste>))))) > > >It "orders" the services by endpoint URL; however, If I uncomment the >lines >marked with //**, nothing changes: > >Teste optimizer >(project (?a) > (union > (union > (service <http://3.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> >< >http://marafo.com/teste>))) > (service <http://2.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> >< >http://marafo.com/teste>)))) > (service <http://1.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < >http://marafo.com/chatuba>))))) > >(project (?a) > (union > (union > (service <http://3.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> >< >http://marafo.com/teste>))) > (service <http://2.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> >< >http://marafo.com/teste>)))) > (service <http://1.com/> > (bgp (triple ?a <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < >http://marafo.com/chatuba>))))) > >I wasn't expecting that the whole thing would be sorted, but at least the >first two OpService should. In case you're wondering, it gets into the IF >that flip the nodes in both cases. > >It's running JENA 2.10.1-SNAPSHOT (apr-4). > >Thanks in advance! > >-- >diogo patrão
