001/**
002 * Copyright 2015 DuraSpace, Inc.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.fcrepo.kernel.modeshape.rdf.impl;
017
018import static org.fcrepo.kernel.api.utils.UncheckedFunction.uncheck;
019import static org.fcrepo.kernel.modeshape.identifiers.NodeResourceConverter.nodeConverter;
020import static org.fcrepo.kernel.modeshape.rdf.converters.ValueConverter.nodeForValue;
021import static java.util.Arrays.asList;
022import static javax.jcr.PropertyType.PATH;
023import static javax.jcr.PropertyType.REFERENCE;
024import static javax.jcr.PropertyType.WEAKREFERENCE;
025
026import com.google.common.collect.Iterators;
027import com.hp.hpl.jena.graph.Triple;
028import com.hp.hpl.jena.rdf.model.Resource;
029import org.fcrepo.kernel.api.identifiers.IdentifierConverter;
030import org.fcrepo.kernel.api.models.FedoraResource;
031import org.fcrepo.kernel.modeshape.rdf.impl.mappings.PropertyToTriple;
032import org.fcrepo.kernel.modeshape.rdf.impl.mappings.PropertyValueIterator;
033
034import javax.jcr.Node;
035import javax.jcr.Property;
036import javax.jcr.RepositoryException;
037import javax.jcr.Value;
038
039import java.util.Iterator;
040import java.util.List;
041import java.util.function.Function;
042import java.util.function.Predicate;
043
044/**
045 * Accumulate inbound references to a given resource
046 *
047 * @author cabeer
048 * @author escowles
049 */
050public class ReferencesRdfContext extends NodeRdfContext {
051
052    private final PropertyToTriple property2triple;
053
054    public static final List<Integer> REFERENCE_TYPES = asList(PATH, REFERENCE, WEAKREFERENCE);
055
056    /**
057     * Add the inbound references from other nodes to this resource to the stream
058     *
059     * @param resource the resource
060     * @param idTranslator the id translator
061     * @throws RepositoryException if repository exception occurred
062     */
063
064    public ReferencesRdfContext(final FedoraResource resource,
065                                final IdentifierConverter<Resource, FedoraResource> idTranslator)
066        throws RepositoryException {
067        super(resource, idTranslator);
068        property2triple = new PropertyToTriple(resource.getNode().getSession(), idTranslator);
069        putReferencesIntoContext(resource.getNode());
070    }
071
072    private final Predicate<Triple> INBOUND = t -> {
073        return t.getObject().getURI().equals(uriFor(resource()).getURI());
074    };
075
076    @SuppressWarnings("unchecked")
077    private void putReferencesIntoContext(final Node node) throws RepositoryException {
078        Iterator<Property> references = node.getReferences();
079        Iterator<Property> weakReferences = node.getWeakReferences();
080        Iterator<Property> allReferences = Iterators.concat(references, weakReferences);
081        concat(flatMap(allReferences, property2triple));
082
083        references = node.getReferences();
084        weakReferences = node.getWeakReferences();
085        allReferences = Iterators.concat(references, weakReferences);
086        concat(Iterators.filter(flatMap(flatMap( allReferences, potentialProxies), triplesForValue), INBOUND::test));
087    }
088
089    /* References from LDP indirect containers are generated dynamically by LdpContainerRdfContext, so they won't
090       show up in getReferences()/getWeakReferences().  Instead, we should check referencers to see if they are
091       members of an IndirectContainer and generate the appropriate inbound references. */
092    @SuppressWarnings("unchecked")
093    private final Function<Property, Iterator<Value>> potentialProxies = uncheck(p -> Iterators.filter(
094            new PropertyValueIterator(p.getParent().getProperties()), v -> REFERENCE_TYPES.contains(v.getType())));
095
096    private final Function<Value, Iterator<Triple>> triplesForValue = uncheck(v ->
097        new LdpContainerRdfContext(nodeConverter.convert(nodeForValue(session(), v)), translator()));
098}