/*
* 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.enrichment;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
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.TripleCollection;
import org.apache.clerezza.rdf.core.UriRef;
import org.apache.clerezza.rdf.core.impl.TripleImpl;
/**
* add a siblingProperty to things with a common parent. every resource with a
* parent is a sibling of itself.
*
* @author reto
*/
public class SiblingEnricher extends Enricher {
//ontology part
/**
* points to the parent of the subject
*/
static UriRef parentProperty = new UriRef("http://example.org/ontology#parent");
static UriRef siblingProperty = new UriRef("http://example.org/ontology#sibling");
/*
* we might be able to tell more about things tht have a parent
*/
@Override
public ResourceFilter getSubjectFilter() {
return getFilterForSubjectsWithProperty(parentProperty);
}
/*
* the only thing we can say is if two things are siblings
*/
@Override
public ResourceFilter getPredicateFilter() {
return getExtensionalFilter(siblingProperty);
}
/*
* the object has a parent too
*/
@Override
public ResourceFilter getObjectFilter() {
return getFilterForSubjectsWithProperty(parentProperty);
}
/*
* the predicate is null or siblingProperty
*/
@Override
public Iterator<Triple> filter(final NonLiteral subject,
final UriRef predicate, final Resource object,
final TripleCollection base) {
if ((subject != null) && (object != null)) {
if (areSiblings(subject, object, base)) {
return Collections.singleton(
(Triple) new TripleImpl(subject, siblingProperty, object)).iterator();
} else {
List<Triple> emptyList = Collections.emptyList();
return emptyList.iterator();
}
} else {
if (subject != null) {
final Iterator<NonLiteral> siblings =
getSiblings(subject, base).iterator();
return new Iterator<Triple>() {
@Override
public boolean hasNext() {
return siblings.hasNext();
}
@Override
public Triple next() {
return new TripleImpl(subject, siblingProperty, siblings.next());
}
@Override
public void remove() {
throw new UnsupportedOperationException(
"cannot delete infered triple");
}
};
}
if (object != null) {
final Iterator<NonLiteral> siblings =
getSiblings((NonLiteral) object,base).iterator();
return new Iterator<Triple>() {
@Override
public boolean hasNext() {
return siblings.hasNext();
}
@Override
public Triple next() {
return new TripleImpl(siblings.next(), siblingProperty, object);
}
@Override
public void remove() {
throw new UnsupportedOperationException(
"cannot delete infered triple");
}
};
}
//both subjecta nd object are null
//TODO
throw new UnsupportedOperationException("not yet pmpliemented");
}
}
private boolean areSiblings(NonLiteral subject, Resource object, TripleCollection base) {
return getSiblings(subject, base).contains(object);
}
private Set<NonLiteral> getSiblings(NonLiteral resource, TripleCollection base) {
Set<Resource> parents = new HashSet<Resource>();
{
Iterator<Triple> parentTriples = base.filter(resource, parentProperty, null);
while (parentTriples.hasNext()) {
parents.add(parentTriples.next().getObject());
}
}
Set<NonLiteral> resultSet = new HashSet<NonLiteral>();
for (Resource parent : parents) {
Iterator<Triple> childTriples = base.filter(null, parentProperty, parent);
while (childTriples.hasNext()) {
resultSet.add(childTriples.next().getSubject());
}
}
return resultSet;
}
@Override
public int providedTriplesCount(TripleCollection base) {
//raw guess
return (int) (base.size() * 0.01);
}
}