The triple to be deleted was previously inferred and is thus contained
in Model newTriples. newTriples is a subModel of OntModel queryModel,
as required by SPINInferences.run().
I found it a bit challenging to override the ARQFactory.getDataset()
method as ARQFactory is a singleton class. The following seems to
work:
MyARQFactory myARQ = new MyARQFactory();
ARQFactory.set(myARQ);
where
public class MyARQFactory extends ARQFactory {
public Dataset getDataset(Model defaultModel) {
OntModel model = (OntModel) defaultModel;
ExtendedIterator<OntModel> i = model.listSubModels();
while(i.hasNext()) {
System.out.println(i.next().toString());
}
...
Dataset d = DatasetFactory.create(model.getBaseModel());
return d;
}
}
My next problem is that getDataset() passes a Model, while an OntModel
is needed to get the subModels. Casting Model to OntModel is probably
not a good idea. Even if it is possible to get an OntModel, how do I
know which subModel is newTriples?
Basically what I'm trying to do is to remove triples that were
previously inferred (based on a CONSTRUCT SPIN rule), when the triple
which caused the inferment does not exist anymore. This should be
quite a common use case, no?
Thanks a lot for your help!
Gerrit
On Aug 26, 1:44 am, Holger Knublauch <[email protected]> wrote:
> Hi Gerrit,
>
> On Aug 25, 2011, at 6:54 PM, Gerrit wrote:
>
> > I have a spin:UpdateTemplate with a DELETE WHERE clause:
>
> > DELETE {
> > ?this sc:hasMediaPath ?mp .
> > }
> > WHERE {
> > ?this sc:hasMediaPath ?mp .
> > ?mp bonding:mediaSourceSO ?mediaSource .
> > ?mp bonding:mediaOriginator ?device2 .
> > FILTER NOT EXISTS {
> > ?this sc:connectedTo ?device2 .
> > } .
> > }
>
> This does not look like a DELETE WHERE. That would be something like
>
> DELETE WHERE {
> ?this sc:hasMediaPath ?mp
>
> }
>
> Anyway, just as an aside because I don't think this is the problem.
>
> > I created the template by subclassing spin:UpdateTemplates and filling
> > in spin:body with the above, and spin:labelTemplate with a human-
> > readable string.
>
> > This seems to work fine in TBC FE. When using it with SPIN 1.2.0, I
> > get the following error:
>
> > Exception in thread "main" java.lang.NullPointerException
> > at org.topbraid.spin.util.UpdateUtil.addUpdatedGraphs(UpdateUtil.java:
> > 58)
>
> That line is
>
> if(quad.isDefaultGraph()) {
> results.add(graphStore.getDefaultModel().getGraph());
>
> }
>
> which indicates to me that your query is trying to update the default graph,
> but your Dataset does not define a default graph. So please either check your
> code where you construct the Dataset to make sure you give it a default
> graph, or change your query so that it explicitly mentions a named graph using
>
> DELETE {
> GRAPH [g] {
> ...
> }}
>
> WHERE {
> ...
>
> }
>
> If the triple you are trying to delete is inferred then it may be in a graph
> that doesn't even have a name in the default Dataset, so you would need to
> overload ARQFactory.getDataset() so that it returns a Dataset that has the
> inferred graph as default graph, or the [g] above.
>
> Cheers,
> Holger
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