/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hp.hpl.jena.sparql.graph;
import java.util.ArrayList ;
import java.util.List ;
import org.slf4j.Logger ;
import org.slf4j.LoggerFactory ;
import com.hp.hpl.jena.graph.* ;
import com.hp.hpl.jena.graph.impl.AllCapabilities ;
import com.hp.hpl.jena.graph.impl.GraphBase ;
import com.hp.hpl.jena.sparql.algebra.Op ;
import com.hp.hpl.jena.sparql.algebra.op.OpBGP ;
import com.hp.hpl.jena.sparql.core.BasicPattern ;
import com.hp.hpl.jena.sparql.core.DatasetGraph ;
import com.hp.hpl.jena.sparql.core.DatasetGraphFactory ;
import com.hp.hpl.jena.sparql.core.Var ;
import com.hp.hpl.jena.sparql.engine.Plan ;
import com.hp.hpl.jena.sparql.engine.QueryEngineFactory ;
import com.hp.hpl.jena.sparql.engine.QueryIterator ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;
import com.hp.hpl.jena.sparql.engine.binding.BindingRoot ;
import com.hp.hpl.jena.util.iterator.ExtendedIterator ;
import com.hp.hpl.jena.util.iterator.WrappedIterator ;
/** This class provides the Jena Graph interface to a graph in a Dataset.
* It enables the full Jena API to be used with data only accessible
* via a Dataset. */
public class GraphSPARQL extends GraphBase implements Graph
{
private static Logger log = LoggerFactory.getLogger(GraphSPARQL.class) ;
private DatasetGraph dataset ;
private QueryEngineFactory factory ;
// Use the dataset graph uninterpretted.
public GraphSPARQL(DatasetGraph dataset, QueryEngineFactory factory)
{
this.dataset = dataset ;
this.factory = factory ;
}
public GraphSPARQL(DatasetGraph dataset, String uri)
{
this(dataset, NodeFactory.createURI(uri)) ;
}
public GraphSPARQL(DatasetGraph dsg, Node gn)
{
this.dataset = DatasetGraphFactory.create(dsg) ;
dataset.setDefaultGraph(dsg.getGraph(gn)) ;
factory = null ;
}
public GraphSPARQL(Graph graph)
{ this(graph, null) ; }
public GraphSPARQL(Graph graph, QueryEngineFactory factory)
{
this.dataset = DatasetGraphFactory.createOneGraph(graph) ;
this.factory = factory ;
}
private DatasetGraph toDSG(DatasetGraph dataset, Node graphNode)
{
Graph graph = ( graphNode == null ) ? dataset.getDefaultGraph() : dataset.getGraph(graphNode) ;
DatasetGraph dsGraph = DatasetGraphFactory.create(graph) ;
return dsGraph ;
}
/* We don't support value tests, hence handlesLiteralTyping is false */
@Override
public Capabilities getCapabilities()
{
if (capabilities == null)
capabilities = new AllCapabilities()
{ @Override
public boolean handlesLiteralTyping() { return false; }
};
return capabilities;
}
public DatasetGraph getDataset() { return dataset ; }
@Override
protected ExtendedIterator<Triple> graphBaseFind(TripleMatch m)
{
Node s = m.getMatchSubject() ;
Var sVar = null ;
if ( s == null )
{
sVar = Var.alloc("s") ;
s = sVar ;
}
Node p = m.getMatchPredicate() ;
Var pVar = null ;
if ( p == null )
{
pVar = Var.alloc("p") ;
p = pVar ;
}
Node o = m.getMatchObject() ;
Var oVar = null ;
if ( o == null )
{
oVar = Var.alloc("o") ;
o = oVar ;
}
Triple triple = new Triple(s, p ,o) ;
// Evaluate as an algebra expression
BasicPattern pattern = new BasicPattern() ;
pattern.add(triple) ;
Op op = new OpBGP(pattern) ;
Plan plan = factory.create(op, getDataset(), BindingRoot.create(), null) ;
QueryIterator qIter = plan.iterator() ;
//List<Triple> triples = new ArrayList<Triple>() ;
List<Triple> triples = new ArrayList<Triple>() ;
for (; qIter.hasNext() ; )
{
Binding b = qIter.nextBinding() ;
Node sResult = s ;
Node pResult = p ;
Node oResult = o ;
if ( sVar != null )
sResult = b.get(sVar) ;
if ( pVar != null )
pResult = b.get(pVar) ;
if ( oVar != null )
oResult = b.get(oVar) ;
Triple resultTriple = new Triple(sResult, pResult, oResult) ;
if ( log.isDebugEnabled() )
log.debug(" "+resultTriple) ;
triples.add(resultTriple) ;
}
qIter.close() ;
return WrappedIterator.createNoRemove(triples.iterator()) ;
}
// class GraphIterator extends TrackingTripleIterator
// {
// GraphIterator(Iterator iter) { super(iter) ; }
//
// @Override
// public void remove()
// { delete((Triple)current) ; }
// }
//
// public StoreLoader getBulkLoader() { return store.getLoader() ; }
//
// @Override
// public BulkUpdateHandler getBulkUpdateHandler()
// {
// if (bulkHandler == null) bulkHandler = new UpdateHandlerSDB(this);
// return bulkHandler;
// }
//
// @Override
// public GraphEventManager getEventManager()
// {
// if (gem == null) gem = new EventManagerSDB( this );
// return gem;
// }
//
// @Override
// public void performAdd( Triple triple )
// {
// if (inBulkUpdate == 0) store.getLoader().startBulkUpdate();
// store.getLoader().addTriple(triple) ;
// if (inBulkUpdate == 0) store.getLoader().finishBulkUpdate();
// }
//
// @Override
// public void performDelete( Triple triple )
// {
// if (inBulkUpdate == 0) store.getLoader().startBulkUpdate();
// store.getLoader().deleteTriple(triple) ;
// if (inBulkUpdate == 0) store.getLoader().finishBulkUpdate();
// }
}