/*
* 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.core;
import java.util.Collection ;
import java.util.Set ;
import com.hp.hpl.jena.graph.Graph ;
import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.query.Dataset ;
import com.hp.hpl.jena.query.DatasetFactory ;
import com.hp.hpl.jena.sparql.ARQConstants ;
import com.hp.hpl.jena.sparql.graph.GraphOps ;
import com.hp.hpl.jena.sparql.graph.GraphUnionRead ;
import com.hp.hpl.jena.sparql.util.NodeUtils ;
public class DynamicDatasets
{
/** Given a Dataset and a query, form a Dataset that
* is the dynamic dataset from the query.
*/
public static Dataset dynamicDataset(DatasetDescription description, Dataset ds, boolean defaultUnionGraph)
{
DatasetGraph dsg = ds.asDatasetGraph() ;
DatasetGraph dsg2 = dynamicDataset(description, dsg, defaultUnionGraph) ;
if ( dsg == dsg2 )
return ds ;
return DatasetFactory.create(dsg2) ;
}
/** Given a DatasetGraph and a query, form a DatasetGraph that
* is the dynamic dataset from the query.
* Returns the original DatasetGraph if the dataset description is null.
*/
public static DatasetGraph dynamicDataset(DatasetDescription description, DatasetGraph dsg, boolean defaultUnionGraph)
{
if ( description == null )
return dsg ;
// //An empty description means leave the dataset as-is
// if (description.getDefaultGraphURIs().size() == 0 && description.getNamedGraphURIs().size() == 0) {
// return dsg;
// }
Set<Node> defaultGraphs = NodeUtils.convertToNodes(description.getDefaultGraphURIs()) ;
Set<Node> namedGraphs = NodeUtils.convertToNodes(description.getNamedGraphURIs()) ;
return dynamicDataset(defaultGraphs, namedGraphs, dsg, defaultUnionGraph) ;
}
/** Given a DatasetGraph and a query, form a DatasetGraph that
* is the dynamic dataset from the collection of graphs from the dataset
* that go to make up the default graph (union) and named graphs.
*/
public static DatasetGraph dynamicDataset(Collection<Node> defaultGraphs, Collection<Node> namedGraphs, DatasetGraph dsg, boolean defaultUnionGraph)
{
Graph dft = new GraphUnionRead(dsg, defaultGraphs) ;
DatasetGraph dsg2 = new DatasetGraphMap(dft) ;
// The named graphs.
for ( Node gn : namedGraphs )
{
Graph g = GraphOps.getGraph(dsg, gn) ;
if ( g != null )
dsg2.addGraph(gn, g) ;
}
if ( dsg.getContext() != null )
dsg2.getContext().putAll(dsg.getContext()) ;
if ( defaultUnionGraph && defaultGraphs.size() == 0 )
{
// Create a union graph - there were no defaultGraphs explicitly named.
Graph unionGraph = new GraphUnionRead(dsg, namedGraphs) ;
dsg2.setDefaultGraph(unionGraph) ;
}
// read-only, <urn:x-arq:DefaultGraph> and <urn:x-arq:UnionGraph> processing.
dsg2 = new DynamicDatasetGraph(dsg2) ;
// Record what we've done.
// c.f. "ARQConstants.sysDatasetDescription" which is used to pass in a DatasetDescription
dsg2.getContext().set(ARQConstants.symDatasetDefaultGraphs, defaultGraphs) ;
dsg2.getContext().set(ARQConstants.symDatasetNamedGraphs, namedGraphs) ;
return dsg2 ;
}
public static class DynamicDatasetGraph extends DatasetGraphReadOnly
{
public DynamicDatasetGraph(DatasetGraph dsg)
{
super(dsg) ;
}
private Graph unionGraph = null ;
@Override
public boolean containsGraph(Node graphNode)
{
if ( Quad.isUnionGraph(graphNode) ) return true ;
if ( Quad.isDefaultGraphExplicit(graphNode)) return true ;
return super.containsGraph(graphNode) ;
}
// See also the GraphOps
@Override
public Graph getGraph(Node graphNode)
{
if ( Quad.isUnionGraph(graphNode) )
{
if ( unionGraph == null )
unionGraph = GraphOps.unionGraph(super.getWrapped()) ;
return unionGraph ;
}
if ( Quad.isDefaultGraphExplicit(graphNode))
return getDefaultGraph() ;
return super.getGraph(graphNode) ;
}
}
}