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 static com.google.common.collect.Lists.newArrayList;
019import static com.hp.hpl.jena.rdf.model.ResourceFactory.createResource;
020
021import com.google.common.base.Converter;
022import com.google.common.collect.Lists;
023
024import org.fcrepo.kernel.models.FedoraResource;
025import org.fcrepo.kernel.exception.RepositoryRuntimeException;
026import org.fcrepo.kernel.identifiers.IdentifierConverter;
027
028import com.hp.hpl.jena.rdf.model.Resource;
029
030import org.fcrepo.kernel.impl.identifiers.HashConverter;
031import org.fcrepo.kernel.impl.identifiers.NamespaceConverter;
032import org.fcrepo.kernel.impl.identifiers.NodeResourceConverter;
033
034import javax.jcr.RepositoryException;
035import javax.jcr.Session;
036
037import java.util.List;
038
039/**
040 * A very simple {@link IdentifierConverter} which translates JCR paths into
041 * un-dereference-able Fedora subjects (by replacing JCR-specific names with
042 * Fedora names). Should not be used except in "embedded" deployments in which
043 * no publication of translated identifiers is expected!
044 *
045 * @author barmintor
046 * @author ajs6f
047 * @since May 15, 2013
048 */
049public class DefaultIdentifierTranslator extends IdentifierConverter<Resource, FedoraResource> {
050
051
052    private static final NodeResourceConverter nodeResourceConverter = new NodeResourceConverter();
053
054    /**
055     * Default namespace to use for node URIs
056     */
057    public static final String RESOURCE_NAMESPACE = "info:fedora/";
058    private final Session session;
059
060    /**
061     * Construct the graph with a placeholder context resource
062     */
063    public DefaultIdentifierTranslator(final Session session) {
064        this.session = session;
065        setTranslationChain();
066    }
067
068
069    protected Converter<String, String> forward = identity();
070    protected Converter<String, String> reverse = identity();
071
072    private void setTranslationChain() {
073
074        for (final Converter<String, String> t : minimalTranslationChain) {
075            forward = forward.andThen(t);
076        }
077        for (final Converter<String, String> t : Lists.reverse(minimalTranslationChain)) {
078            reverse = reverse.andThen(t.reverse());
079        }
080    }
081
082
083    @SuppressWarnings("unchecked")
084    private static final List<Converter<String, String>> minimalTranslationChain =
085            newArrayList((Converter<String, String>) new NamespaceConverter(),
086                    (Converter<String, String>) new HashConverter()
087            );
088
089    @Override
090    protected FedoraResource doForward(final Resource subject) {
091        try {
092            if (!inDomain(subject)) {
093                throw new RepositoryRuntimeException("Subject " + subject + " is not in this repository");
094            }
095
096            return nodeResourceConverter.convert(session.getNode(asString(subject)));
097        } catch (final RepositoryException e) {
098            throw new RepositoryRuntimeException(e);
099        }
100    }
101
102    @Override
103    protected Resource doBackward(final FedoraResource resource) {
104        final String absPath = resource.getPath();
105
106        return toDomain(absPath);
107    }
108
109    @Override
110    public boolean inDomain(final Resource subject) {
111        return subject.isURIResource() && subject.getURI().startsWith(RESOURCE_NAMESPACE);
112    }
113
114    @Override
115    public Resource toDomain(final String absPath) {
116        final String relativePath;
117
118        if (absPath.startsWith("/")) {
119            relativePath = absPath.substring(1);
120        } else {
121            relativePath = absPath;
122        }
123        return createResource(RESOURCE_NAMESPACE + reverse.convert(relativePath));
124    }
125
126    @Override
127    public String asString(final Resource subject) {
128        if (!inDomain(subject)) {
129            return null;
130        }
131
132        final String path = subject.getURI().substring(RESOURCE_NAMESPACE.length() - 1);
133
134        final String absPath = forward.convert(path);
135
136        if (absPath.isEmpty()) {
137            return "/";
138        }
139        return absPath;
140    }
141
142}