it.uniroma2.art.owlart.utilities.RDFIterators Maven / Gradle / Ivy
/*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
* the specific language governing rights and limitations under the License.
*
* The Original Code is ART OWL API.
*
* The Initial Developer of the Original Code is University of Roma Tor Vergata.
* Portions created by University of Roma Tor Vergata are Copyright (C) 2009.
* All Rights Reserved.
*
* The ART OWL API were developed by the Artificial Intelligence Research Group
* (art.uniroma2.it) at the University of Roma Tor Vergata
* Current information about the ART OWL API can be obtained at
* http://art.uniroma2.it/owlart
*
*/
package it.uniroma2.art.owlart.utilities;
import it.uniroma2.art.owlart.exceptions.ModelAccessException;
import it.uniroma2.art.owlart.model.ARTBNode;
import it.uniroma2.art.owlart.model.ARTLiteral;
import it.uniroma2.art.owlart.model.ARTNode;
import it.uniroma2.art.owlart.model.ARTResource;
import it.uniroma2.art.owlart.model.ARTStatement;
import it.uniroma2.art.owlart.model.ARTURIResource;
import it.uniroma2.art.owlart.models.OWLModel;
import it.uniroma2.art.owlart.models.impl.LiteralIteratorFilteringNodeIterator;
import it.uniroma2.art.owlart.models.impl.LiteralIteratorWrappingNodeIterator;
import it.uniroma2.art.owlart.models.impl.NodesOfStatementsIterator;
import it.uniroma2.art.owlart.models.impl.OWLModelImpl;
import it.uniroma2.art.owlart.models.impl.ObjectsOfStatementsIterator;
import it.uniroma2.art.owlart.models.impl.PredicatesOfStatementsIterator;
import it.uniroma2.art.owlart.models.impl.ResourceIteratorFilteringNodeIterator;
import it.uniroma2.art.owlart.models.impl.ResourceIteratorWrappingNodeIterator;
import it.uniroma2.art.owlart.models.impl.SubjectsOfStatementsIterator;
import it.uniroma2.art.owlart.models.impl.URIResourceIteratorFilteringNodeIterator;
import it.uniroma2.art.owlart.models.impl.URIResourceIteratorFilteringResourceIterator;
import it.uniroma2.art.owlart.models.impl.URIResourceIteratorWrappingNodeIterator;
import it.uniroma2.art.owlart.models.impl.URIResourceIteratorWrappingResourceIterator;
import it.uniroma2.art.owlart.navigation.ARTBNodeIterator;
import it.uniroma2.art.owlart.navigation.ARTLiteralIterator;
import it.uniroma2.art.owlart.navigation.ARTNodeIterator;
import it.uniroma2.art.owlart.navigation.ARTResourceIterator;
import it.uniroma2.art.owlart.navigation.ARTStatementIterator;
import it.uniroma2.art.owlart.navigation.ARTURIResourceIterator;
import it.uniroma2.art.owlart.navigation.RDFIterator;
import it.uniroma2.art.owlart.navigation.RDFIteratorImpl;
import it.uniroma2.art.owlart.vocabulary.RDF;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Set;
/**
* Utility methods for managing {@link RDFIterator}s
*
* @author Armando Stellato
*
*/
public class RDFIterators {
/**
* this method obtains a collection of objects extracted from an {@link RDFIterator}. Note that the
* RDFIterator is automatically closed at the end of execution of this method
*
* @param
* @param rdfIt
* @return
* @throws ModelAccessException
*/
public static void addIteratorToCollection(RDFIterator rdfIt, Collection collection)
throws ModelAccessException {
while (rdfIt.streamOpen()) {
collection.add(rdfIt.getNext());
}
rdfIt.close();
}
public static T getFirst(RDFIterator rdfIt) throws ModelAccessException {
T result = null;
if (rdfIt.streamOpen())
result = rdfIt.getNext();
rdfIt.close();
return result;
}
/**
* this method obtains a collection of objects extracted from an {@link RDFIterator}. Note that the
* RDFIterator is automatically closed at the end of execution of this method
*
* @param
* @param rdfIt
* @return
* @throws ModelAccessException
*/
public static Collection getCollectionFromIterator(RDFIterator rdfIt)
throws ModelAccessException {
ArrayList collection = new ArrayList();
while (rdfIt.streamOpen()) {
collection.add(rdfIt.getNext());
}
rdfIt.close();
return collection;
}
/**
* this method obtains a set of objects (i.e. removes duplicates) extracted from an {@link RDFIterator}.
* Note that the RDFIterator is automatically closed at the end of execution of this method
*
* @param
* @param rdfIt
* @return
* @throws ModelAccessException
*/
public static Set getSetFromIterator(RDFIterator rdfIt) throws ModelAccessException {
HashSet set = new HashSet();
while (rdfIt.streamOpen()) {
set.add(rdfIt.getNext());
}
rdfIt.close();
return set;
}
/**
* creates an ARTNodeIterator iterating over all the elements pointed by list saving all the
* code needed to parse the list RDF structure
*
* @param model
* @param list
* @param inference
* @param graphs
* @return
* @throws ModelAccessException
*/
public static ARTNodeIterator createRDFListIterator(OWLModel model, ARTResource list, boolean inference,
ARTResource... graphs) throws ModelAccessException {
return new RDFListIterator(model, list, inference, graphs);
}
/**
* This is to be used if the developer knows in advance that wrapped iterator contains only Literals. It
* is more performant than the {@link #filterLiterals(ARTNodeIterator)} call because it omits checks on
* the nature of the wrapped nodes, expecting them to be Literals
*
* @param it
* @return
* @throws ModelAccessException
*/
public static ARTLiteralIterator toLiteralIterator(ARTNodeIterator it) throws ModelAccessException {
return new LiteralIteratorWrappingNodeIterator(it);
}
/**
* This is to be used if the developer knows in advance that wrapped iterator contains only Resources. It
* is more performant than the {@link #filterResources(ARTNodeIterator)} call because it omits checks on
* the nature of the wrapped nodes, expecting them to be Resources
*
* @param it
* @return
* @throws ModelAccessException
*/
public static ARTResourceIterator toResourceIterator(ARTNodeIterator it) throws ModelAccessException {
return new ResourceIteratorWrappingNodeIterator(it);
}
/**
* This is to be used if the developer knows in advance that wrapped iterator contains only URIs. It is
* more performant than the {@link #filterURIs(ARTNodeIterator)} call because it omits checks on the
* nature of the wrapped nodes, expecting them to be URIs
*
* @param it
* @return
* @throws ModelAccessException
*/
public static ARTURIResourceIterator toURIResourceIterator(ARTNodeIterator it)
throws ModelAccessException {
return new URIResourceIteratorWrappingNodeIterator(it);
}
/**
* This is to be used if the developer knows in advance that wrapped iterator contains only URIs. It is
* more performant than the {@link #filterURIs(ARTResourceIterator)} call because it omits checks on the
* nature of the wrapped nodes, expecting them to be URIs
*
* @param it
* @return
* @throws ModelAccessException
*/
public static ARTURIResourceIterator toURIResourceIterator(ARTResourceIterator it)
throws ModelAccessException {
return new URIResourceIteratorWrappingResourceIterator(it);
}
/**
* this filtered iterator passes only {@link ARTLiteral}s out of a generic {@link ARTNodeIterator}
*
* @param it
* @return
* @throws ModelAccessException
*/
public static ARTLiteralIterator filterLiterals(ARTNodeIterator it) throws ModelAccessException {
return new LiteralIteratorFilteringNodeIterator(it);
}
/**
* this filtered iterator passes only {@link ARTResource}s out of a generic {@link ARTNodeIterator}
*
* @param it
* @return
* @throws ModelAccessException
*/
public static ARTResourceIterator filterResources(ARTNodeIterator it) throws ModelAccessException {
return new ResourceIteratorFilteringNodeIterator(it);
}
/**
* this filtered iterator passes only {@link ARTURIResource}s out of a generic {@link ARTNodeIterator}
*
* @param it
* @return
* @throws ModelAccessException
*/
public static ARTURIResourceIterator filterURIs(ARTNodeIterator it) throws ModelAccessException {
return new URIResourceIteratorFilteringNodeIterator(it);
}
/**
* this filtered iterator passes only {@link ARTURIResource}s out of a generic {@link ARTResourceIterator}
*
* @param it
* @return
* @throws ModelAccessException
*/
public static ARTURIResourceIterator filterURIs(ARTResourceIterator it) throws ModelAccessException {
return new URIResourceIteratorFilteringResourceIterator(it);
}
public static ARTResourceIterator listSubjects(ARTStatementIterator statIt) {
return new SubjectsOfStatementsIterator(statIt);
}
public static ARTURIResourceIterator listPredicates(ARTStatementIterator statIt) {
return new PredicatesOfStatementsIterator(statIt);
}
public static ARTNodeIterator listObjects(ARTStatementIterator statIt) {
return new ObjectsOfStatementsIterator(statIt);
}
public static ARTNodeIterator listNodes(ARTStatementIterator statIt) {
return new NodesOfStatementsIterator(statIt);
}
public static ARTNodeIterator createARTNodeIterator(RDFIterator it) {
return new ARTNodeIteratorImpl(it);
}
public static ARTNodeIterator createARTNodeIterator(Iterator it) {
return new ARTNodeIteratorWrappingStdIteratorImpl(it);
}
public static ARTBNodeIterator createARTBNodeIterator(RDFIterator it) {
return new ARTBNodeIteratorImpl(it);
}
public static ARTResourceIterator createARTResourceIterator(RDFIterator it) {
return new ARTResourceIteratorImpl(it);
}
public static ARTURIResourceIterator createARTURIResourceIterator(RDFIterator it) {
return new ARTURIResourceIteratorImpl(it);
}
public static ARTURIResourceIterator createARTURIResourceIterator(Iterator it) {
return new ARTURIResourceIteratorWrappingStdIteratorImpl(it);
}
public static ARTLiteralIterator createARTLiteralIterator(RDFIterator it) {
return new ARTLiteralIteratorImpl(it);
}
public static ARTLiteralIterator createARTLiteralIterator(Iterator it) {
return new ARTLiteralIteratorWrappingStdIteratorImpl(it);
}
public static ARTStatementIterator createARTStatementIterator(RDFIterator it) {
return new ARTStatementIteratorImpl(it);
}
public static ARTStatementIterator createARTStatementIterator(Iterator it) {
return new ARTStatementIteratorNormalIteratorImpl(it);
}
/**
* @param
* @param it1
* @param it2
* @return an iterator iterating over the concatenation of results from it1 and
* it2.
*/
public static RDFIterator concat(RDFIterator it1, RDFIterator it2) {
ConcatenatedRDFIterator it = new ConcatenatedRDFIterator(it1, it2);
return it;
}
/**
* @param it
* @param singleton
* @return an iterator iterating over elements in iterator it plus the single element
* singleton (tailed to them)
*/
public static RDFIterator concat(RDFIterator it, T singleton) {
ConcatenatedRDFIterator concIt = new ConcatenatedRDFIterator(it, new SingletonRDFIterator(
singleton));
return concIt;
}
/**
* @param singleton
* @param it
* @return an iterator iterating over elements in iterator it plus the single element
* singleton (put in the head)
*/
public static RDFIterator concat(T singleton, RDFIterator it) {
ConcatenatedRDFIterator concIt = new ConcatenatedRDFIterator(new SingletonRDFIterator(
singleton), it);
return concIt;
}
private static class SingletonRDFIterator extends RDFIteratorImpl {
boolean returned;
T singleton;
SingletonRDFIterator(T singleton) {
this.singleton = singleton;
}
public boolean streamOpen() throws ModelAccessException {
return !returned;
}
public T getNext() throws ModelAccessException {
returned = true;
return singleton;
}
public void close() throws ModelAccessException {
}
}
private static class ConcatenatedRDFIterator extends RDFIteratorImpl {
RDFIterator it1;
RDFIterator it2;
RDFIterator currentIterator;
ConcatenatedRDFIterator(RDFIterator it1, RDFIterator it2) {
this.it1 = it1;
this.it2 = it2;
currentIterator = it1;
}
public boolean streamOpen() throws ModelAccessException {
if (currentIterator.streamOpen())
return true;
if (currentIterator == it1) {
it1.close();
currentIterator = it2;
return it2.streamOpen();
}
return false;
}
public T getNext() throws ModelAccessException {
try {
return currentIterator.getNext();
} catch (NoSuchElementException e) {
if (currentIterator == it1) {
// there's no guarantee that a call to getNext has been anticipated by a check with
// streamOpen(), so it is mandatory to redo the check, just in case a
// NoSuchElementException is launched
it1.close();
currentIterator = it2;
return it2.getNext();
}
// if currentIterator was already it2, re-throw the exception
throw new NoSuchElementException(e.getMessage());
}
}
public void close() throws ModelAccessException {
it1.close();
it2.close();
}
}
/**
* returns an iterator with removed duplicates from it
*
* @param it
* @return
*/
public static ARTNodeIterator listDistinct(ARTNodeIterator it) {
return createARTNodeIterator(new DistinctRDFIterator(it));
}
/**
* returns an iterator with removed duplicates from it
*
* @param it
* @return
*/
public static ARTURIResourceIterator listDistinct(ARTURIResourceIterator it) {
return createARTURIResourceIterator(new DistinctRDFIterator(it));
}
/**
* returns an iterator with removed duplicates from it
*
* @param it
* @return
*/
public static ARTResourceIterator listDistinct(ARTResourceIterator it) {
return createARTResourceIterator(new DistinctRDFIterator(it));
}
public static class DistinctRDFIterator extends RDFIteratorImpl {
HashSet explored;
RDFIterator resIt;
T capsule = null;
DistinctRDFIterator(RDFIterator it) {
this.resIt = it;
explored = new HashSet();
}
public void close() throws ModelAccessException {
resIt.close();
}
public boolean streamOpen() throws ModelAccessException {
T temp;
while (resIt.streamOpen() == true && capsule == null) {
temp = resIt.next();
if (!explored.contains(temp)) {
capsule = temp;
explored.add(temp);
}
}
if (capsule != null)
return true;
else
return false;
}
public T getNext() throws ModelAccessException {
T temp = capsule;
capsule = null;
return temp;
}
}
/**
* This iterator class provides facilities for managing resources of type rdf:List It is already used in
* OWL and SKOS methods such as {@link OWLModelImpl#parseDataRange(ARTResource, ARTResource...)}
*
* @author Armando Stellato
*
*/
public static class RDFListIterator extends RDFIteratorImpl implements ARTNodeIterator {
ARTResource currentNode;
OWLModel model;
boolean inference;
ARTResource[] graphs;
public RDFListIterator(OWLModel model, ARTResource list, boolean inference, ARTResource... graphs)
throws ModelAccessException {
this.model = model;
this.graphs = graphs;
this.inference = inference;
currentNode = list;
}
public void close() throws ModelAccessException {
}
public ARTNode getNext() throws ModelAccessException {
if (!streamOpen())
throw new ModelAccessException("cannot access next node of the list since there are no more!");
// getting value of current node
ARTNodeIterator it = model
.listValuesOfSubjPredPair(currentNode, RDF.Res.FIRST, inference, graphs);
ARTNode currentValue = it.getNext();
it.close();
// updating current node
ARTResourceIterator resIt = model.listValuesOfSubjObjPropertyPair(currentNode, RDF.Res.REST,
inference, graphs);
currentNode = resIt.getNext();
resIt.close();
return currentValue;
}
public boolean streamOpen() throws ModelAccessException {
if (currentNode.equals(RDF.Res.NIL))
return false;
return true;
}
}
private static class ARTNodeIteratorImpl extends RDFIteratorImpl implements ARTNodeIterator {
RDFIterator it;
ARTNodeIteratorImpl(RDFIterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.streamOpen();
}
public ARTNode getNext() throws ModelAccessException {
return it.getNext();
}
public void close() throws ModelAccessException {
it.close();
}
}
private static class ARTNodeIteratorWrappingStdIteratorImpl extends RDFIteratorImpl implements
ARTNodeIterator {
Iterator it;
ARTNodeIteratorWrappingStdIteratorImpl(Iterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.hasNext();
}
public ARTNode getNext() throws ModelAccessException {
return it.next();
}
public void close() throws ModelAccessException {
// it.close();
}
}
private static class ARTBNodeIteratorImpl extends RDFIteratorImpl implements ARTBNodeIterator {
RDFIterator it;
ARTBNodeIteratorImpl(RDFIterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.streamOpen();
}
public ARTBNode getNext() throws ModelAccessException {
return it.getNext();
}
public void close() throws ModelAccessException {
it.close();
}
}
private static class ARTResourceIteratorImpl extends RDFIteratorImpl implements
ARTResourceIterator {
RDFIterator it;
ARTResourceIteratorImpl(RDFIterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.streamOpen();
}
public ARTResource getNext() throws ModelAccessException {
return it.getNext();
}
public void close() throws ModelAccessException {
it.close();
}
}
private static class ARTURIResourceIteratorWrappingStdIteratorImpl extends
RDFIteratorImpl implements ARTURIResourceIterator {
Iterator it;
ARTURIResourceIteratorWrappingStdIteratorImpl(Iterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.hasNext();
}
public ARTURIResource getNext() throws ModelAccessException {
return it.next();
}
public void close() throws ModelAccessException {
// it.close();
}
}
private static class ARTURIResourceIteratorImpl extends RDFIteratorImpl implements
ARTURIResourceIterator {
RDFIterator it;
ARTURIResourceIteratorImpl(RDFIterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.streamOpen();
}
public ARTURIResource getNext() throws ModelAccessException {
return it.getNext();
}
public void close() throws ModelAccessException {
it.close();
}
}
private static class ARTLiteralIteratorImpl extends RDFIteratorImpl implements
ARTLiteralIterator {
RDFIterator it;
ARTLiteralIteratorImpl(RDFIterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.streamOpen();
}
public ARTLiteral getNext() throws ModelAccessException {
return it.getNext();
}
public void close() throws ModelAccessException {
it.close();
}
}
private static class ARTLiteralIteratorWrappingStdIteratorImpl extends RDFIteratorImpl
implements ARTLiteralIterator {
Iterator it;
ARTLiteralIteratorWrappingStdIteratorImpl(Iterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.hasNext();
}
public ARTLiteral getNext() throws ModelAccessException {
return it.next();
}
public void close() throws ModelAccessException {
// it.close();
}
}
private static class ARTStatementIteratorImpl extends RDFIteratorImpl implements
ARTStatementIterator {
RDFIterator it;
ARTStatementIteratorImpl(RDFIterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.streamOpen();
}
public ARTStatement getNext() throws ModelAccessException {
return it.getNext();
}
public void close() throws ModelAccessException {
it.close();
}
}
private static class ARTStatementIteratorNormalIteratorImpl extends RDFIteratorImpl
implements ARTStatementIterator {
Iterator it;
ARTStatementIteratorNormalIteratorImpl(Iterator it) {
this.it = it;
}
public boolean streamOpen() throws ModelAccessException {
return it.hasNext();
}
public ARTStatement getNext() throws ModelAccessException {
return it.next();
}
public void close() throws ModelAccessException {
}
}
}
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