/*
* 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 org.apache.clerezza.rdf.jena.storage;
import com.hp.hpl.jena.graph.BulkUpdateHandler;
import com.hp.hpl.jena.graph.Graph;
import com.hp.hpl.jena.graph.Node;
import com.hp.hpl.jena.util.iterator.ExtendedIterator;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import org.apache.clerezza.rdf.core.BNode;
import org.apache.clerezza.rdf.core.NonLiteral;
import org.apache.clerezza.rdf.core.Resource;
import org.apache.clerezza.rdf.core.Triple;
import org.apache.clerezza.rdf.core.UriRef;
import org.apache.clerezza.rdf.core.impl.AbstractMGraph;
import org.apache.clerezza.rdf.jena.commons.Jena2TriaUtil;
import org.apache.clerezza.rdf.jena.commons.Tria2JenaUtil;
import org.wymiwyg.commons.util.collections.BidiMap;
import org.wymiwyg.commons.util.collections.BidiMapImpl;
/**
* An adaptor to expose a Jena Graph as Clerezza MGraph.
*
* @author rbn
*/
public class JenaGraphAdaptor extends AbstractMGraph {
private final Graph jenaGraph;
final BidiMap<BNode, Node> tria2JenaBNodes = new BidiMapImpl<BNode, Node>();
final Jena2TriaUtil jena2TriaUtil =
new Jena2TriaUtil(tria2JenaBNodes.inverse());
final Tria2JenaUtil tria2JenaUtil =
new Tria2JenaUtil(tria2JenaBNodes);
/**
* Constructs an MGraph based on the supplied jena Graph.
*
* @param jenaGraph
*/
public JenaGraphAdaptor(Graph jenaGraph) {
this.jenaGraph = jenaGraph;
}
@Override
public void clear() {
super.clear();
tria2JenaBNodes.clear();
}
@Override
public int size() {
return jenaGraph.size();
}
@Override
public Iterator<Triple> performFilter(NonLiteral subject, UriRef predicate, Resource object) {
Node jenaSubject = null;
Node jenaPredicate = null;
Node jenaObject = null;
if (subject != null) {
jenaSubject = tria2JenaUtil.convert2JenaNode(subject);
if (jenaSubject == null) {
return Collections.EMPTY_SET.iterator();
}
}
if (object != null) {
jenaObject = tria2JenaUtil.convert2JenaNode(object);
if (jenaObject == null) {
return Collections.EMPTY_SET.iterator();
}
}
if (predicate != null) {
jenaPredicate = tria2JenaUtil.convert2JenaNode(predicate);
}
final ExtendedIterator jenaIter = jenaGraph.find(jenaSubject, jenaPredicate,
jenaObject);
return new Iterator<Triple>() {
private Triple lastReturned = null;
private Iterator<Triple> precached = null;
@Override
public boolean hasNext() {
if (precached != null) {
return precached.hasNext();
} else {
return jenaIter.hasNext();
}
}
@Override
public Triple next() {
if (precached != null) {
lastReturned = precached.next();
} else {
lastReturned = jena2TriaUtil.convertTriple(
(com.hp.hpl.jena.graph.Triple)jenaIter.next());
}
return lastReturned;
}
@Override
public void remove() {
final Triple deleting = lastReturned;
if (precached == null) {
final ArrayList<Triple> data = new ArrayList<Triple>();
while (hasNext()) {
data.add(next());
}
precached = data.iterator();
}
//jenaIter.remove();
//JenaGraphAdaptor.this.performRemove(lastReturned);
jenaGraph.delete(tria2JenaUtil.convertTriple(deleting));
}
};
}
@Override
public boolean performAdd(Triple triple) {
if (contains(triple)) {
return false;
}
jenaGraph.add(tria2JenaUtil.convertTriple(triple, true));
return true;
}
@Override
public boolean performRemove(Triple triple) {
if (!contains(triple)) {
return false;
}
jenaGraph.delete(tria2JenaUtil.convertTriple(triple));
return true;
}
}