On 27/08/13 17:16, Rob Vesse wrote:
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
Yes. In
public Op transform(OpUnion opUnion, Op left, Op right)
opUnion is the original input, and left/right the new sub ops due to the
transforming the elements below this union, so you can see both original
and sub-writes.
Andy
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
