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.impl.rdf.impl;
017
018import com.google.common.base.Function;
019import com.google.common.collect.Iterators;
020import com.hp.hpl.jena.graph.Triple;
021import com.hp.hpl.jena.rdf.model.Resource;
022import org.fcrepo.kernel.models.NonRdfSourceDescription;
023import org.fcrepo.kernel.models.FedoraResource;
024import org.fcrepo.kernel.identifiers.IdentifierConverter;
025import org.fcrepo.kernel.utils.iterators.RdfStream;
026import org.slf4j.Logger;
027
028import javax.jcr.RepositoryException;
029
030import java.util.Iterator;
031
032import static com.hp.hpl.jena.graph.Triple.create;
033import static org.fcrepo.kernel.RdfLexicon.CONTAINS;
034import static org.slf4j.LoggerFactory.getLogger;
035
036/**
037 * @author cabeer
038 * @since 9/16/14
039 */
040public class ChildrenRdfContext extends NodeRdfContext {
041
042    private static final Logger LOGGER = getLogger(ChildrenRdfContext.class);
043
044    /**
045     * Default constructor.
046     *
047     * @param resource the resource
048     * @param idTranslator the idTranslator
049     * @throws javax.jcr.RepositoryException if repository exception occurred
050     */
051    public ChildrenRdfContext(final FedoraResource resource,
052                              final IdentifierConverter<Resource, FedoraResource> idTranslator)
053            throws RepositoryException {
054        super(resource, idTranslator);
055
056        if (resource.getNode().hasNodes()) {
057            LOGGER.trace("Found children of this resource.");
058            concat(childrenContext());
059        }
060    }
061
062
063    private Iterator<Triple> childrenContext() {
064
065        final Iterator<FedoraResource> niceChildren = resource().getChildren();
066
067        return Iterators.concat(Iterators.transform(niceChildren, child2triples()));
068    }
069
070    private Function<FedoraResource, Iterator<Triple>> child2triples() {
071        return new Function<FedoraResource, Iterator<Triple>>() {
072
073            @Override
074            public Iterator<Triple> apply(final FedoraResource child) {
075
076                final com.hp.hpl.jena.graph.Node childSubject;
077
078                if (child instanceof NonRdfSourceDescription) {
079                    childSubject = translator().reverse()
080                            .convert(((NonRdfSourceDescription) child).getDescribedResource())
081                            .asNode();
082                } else {
083                    childSubject = translator().reverse().convert(child).asNode();
084                }
085                LOGGER.trace("Creating triples for child node: {}", child);
086                final RdfStream childStream = new RdfStream();
087                childStream.concat(create(subject(), CONTAINS.asNode(), childSubject));
088                return childStream;
089            }
090        };
091    }
092
093}