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 com.google.common.collect.Iterators;
019import com.hp.hpl.jena.graph.Triple;
020import com.hp.hpl.jena.rdf.model.Resource;
021import org.fcrepo.kernel.api.models.NonRdfSourceDescription;
022import org.fcrepo.kernel.api.models.FedoraResource;
023import org.fcrepo.kernel.api.identifiers.IdentifierConverter;
024import org.slf4j.Logger;
025
026import javax.jcr.RepositoryException;
027
028import java.util.Iterator;
029import java.util.function.Function;
030
031import static com.hp.hpl.jena.datatypes.xsd.XSDDatatype.XSDint;
032import static com.hp.hpl.jena.graph.Triple.create;
033import static com.hp.hpl.jena.rdf.model.ResourceFactory.createTypedLiteral;
034import static org.fcrepo.kernel.api.RdfLexicon.CONTAINS;
035import static org.fcrepo.kernel.api.RdfLexicon.HAS_CHILD_COUNT;
036import static org.slf4j.LoggerFactory.getLogger;
037
038/**
039 * @author cabeer
040 * @author ajs6f
041 * @since 9/16/14
042 */
043public class ChildrenRdfContext extends NodeRdfContext {
044
045    private static final Logger LOGGER = getLogger(ChildrenRdfContext.class);
046
047    /**
048     * Default constructor.
049     *
050     * @param resource the resource
051     * @param idTranslator the idTranslator
052     * @throws javax.jcr.RepositoryException if repository exception occurred
053     */
054    public ChildrenRdfContext(final FedoraResource resource,
055                              final IdentifierConverter<Resource, FedoraResource> idTranslator)
056            throws RepositoryException {
057        super(resource, idTranslator);
058
059        if (resource.getNode().hasNodes()) {
060            LOGGER.trace("Found children of this resource: {}", resource.getPath());
061
062            // Count the number of children
063            final Iterator<FedoraResource> childrenCounter = resource().getChildren();
064            concat(createNumChildrenTriple(Iterators.size(childrenCounter)));
065
066            final Iterator<FedoraResource> niceChildren = resource().getChildren();
067            concat(Iterators.transform(niceChildren, child2triple::apply));
068
069        } else {
070            concat(createNumChildrenTriple(0));
071        }
072
073
074    }
075
076    private Triple createNumChildrenTriple(final int numChildren) {
077        return create(subject(),
078                HAS_CHILD_COUNT.asNode(),
079                createTypedLiteral(Integer.toString(numChildren), XSDint).asNode());
080    }
081
082    private final Function<FedoraResource, Triple> child2triple = child -> {
083
084        final com.hp.hpl.jena.graph.Node childSubject = child instanceof NonRdfSourceDescription ?
085                uriFor(((NonRdfSourceDescription) child).getDescribedResource()) : uriFor(child);
086
087        LOGGER.trace("Creating triple for child node: {}", child);
088        return create(subject(), CONTAINS.asNode(), childSubject);
089    };
090}