Re: ERROR: Quad: object cannot be null

[Minto van der Sluis]

This time I end up with an NPE, see stack below.

My changes resulted in the following

    public Object executeSparqlQuery(String query, TripleCollection
defaultGraph, boolean forceFastlane) throws ParseException {
        TcProvider singleTargetTcProvider = null;
        if (forceFastlane) {
            singleTargetTcProvider = getSingleTargetTcProvider();
        } else {       
            final UriRef defaultGraphName = new
UriRef("urn:x-temp:/kjsfadfhfasdffds");
            SparqlPreParser sparqlPreParser = new SparqlPreParser(this);
            final Set<UriRef> referencedGraphs =
sparqlPreParser.getReferredGraphs(query, defaultGraphName);
            if ((referencedGraphs != null) &&
(!referencedGraphs.contains(defaultGraphName))) {
                singleTargetTcProvider =
getSingleTargetTcProvider(referencedGraphs);
            }
        }
       
        if ((singleTargetTcProvider != null) && (singleTargetTcProvider
instanceof QueryableTcProvider)) {
            return
((QueryableTcProvider)singleTargetTcProvider).executeSparqlQuery(query,
null);
        }
        final QueryEngine queryEngine = this.queryEngine;
        if (queryEngine != null) {
            return queryEngine.execute(this, defaultGraph, query);
        } else {
            throw new NoQueryEngineException();
        }
    }

   private TcProvider getSingleTargetTcProvider() {
        return providerList.first();
    }

I guess the following like in BaseTdbTcProvider.executeSparqlQuery() is
the culprit:

       getDataset().setDefaultModel(null);

Stacktrace:

java.lang.NullPointerException
    at
com.hp.hpl.jena.sparql.core.DatasetImpl.addToCache(DatasetImpl.java:259)
    at
com.hp.hpl.jena.sparql.core.DatasetImpl.setDefaultModel(DatasetImpl.java:214)
    at
org.apache.clerezza.rdf.jena.tdb.storage.BaseTdbTcProvider.executeSparqlQuery(BaseTdbTcProvider.java:39)
    at
org.apache.clerezza.rdf.jena.tdb.storage.ScalableSingleTdbDatasetTcProvider.executeSparqlQuery(ScalableSingleTdbDatasetTcProvider.java:81)
    at
org.apache.clerezza.rdf.core.access.TcManager.executeSparqlQuery(TcManager.java:310)
    at
org.apache.clerezza.rdf.core.access.TcManager.executeSparqlQuery(TcManager.java:282)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)[:1.7.0_17]
    at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)[:1.7.0_17]
    at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)[:1.7.0_17]
    at java.lang.reflect.Method.invoke(Method.java:601)[:1.7.0_17]
    at
org.apache.aries.proxy.impl.ProxyHandler$1.invoke(ProxyHandler.java:54)[12:org.apache.aries.proxy.impl:1.0.0]
    at
org.apache.aries.proxy.impl.ProxyHandler.invoke(ProxyHandler.java:119)[12:org.apache.aries.proxy.impl:1.0.0]
    at
org.apache.clerezza.rdf.core.access.$TcManager10360330.executeSparqlQuery(Unknown
Source)[181:org.apache.clerezza.rdf.core:0.13.0.SNAPSHOT]
    at
nl.overheid.stelsel.digimelding.astore.storage.clerezza.ClerezzaStorageProvider.query(ClerezzaStorageProvider.java:250)[209:astore-storage-clerezza:0.7.0.SNAPSHOT]