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     * @param session the session
063     */
064    public DefaultIdentifierTranslator(final Session session) {
065        this.session = session;
066        setTranslationChain();
067    }
068
069
070    protected Converter<String, String> forward = identity();
071    protected Converter<String, String> reverse = identity();
072
073    private void setTranslationChain() {
074
075        for (final Converter<String, String> t : minimalTranslationChain) {
076            forward = forward.andThen(t);
077        }
078        for (final Converter<String, String> t : Lists.reverse(minimalTranslationChain)) {
079            reverse = reverse.andThen(t.reverse());
080        }
081    }
082
083
084    @SuppressWarnings("unchecked")
085    private static final List<Converter<String, String>> minimalTranslationChain =
086            newArrayList((Converter<String, String>) new NamespaceConverter(),
087                    (Converter<String, String>) new HashConverter()
088            );
089
090    @Override
091    protected FedoraResource doForward(final Resource subject) {
092        try {
093            if (!inDomain(subject)) {
094                throw new RepositoryRuntimeException("Subject " + subject + " is not in this repository");
095            }
096
097            return nodeResourceConverter.convert(session.getNode(asString(subject)));
098        } catch (final RepositoryException e) {
099            throw new RepositoryRuntimeException(e);
100        }
101    }
102
103    @Override
104    protected Resource doBackward(final FedoraResource resource) {
105        final String absPath = resource.getPath();
106
107        return toDomain(absPath);
108    }
109
110    @Override
111    public boolean inDomain(final Resource subject) {
112        return subject.isURIResource() && subject.getURI().startsWith(RESOURCE_NAMESPACE);
113    }
114
115    @Override
116    public Resource toDomain(final String absPath) {
117        final String relativePath;
118
119        if (absPath.startsWith("/")) {
120            relativePath = absPath.substring(1);
121        } else {
122            relativePath = absPath;
123        }
124        return createResource(RESOURCE_NAMESPACE + reverse.convert(relativePath));
125    }
126
127    @Override
128    public String asString(final Resource subject) {
129        if (!inDomain(subject)) {
130            return null;
131        }
132
133        final String path = subject.getURI().substring(RESOURCE_NAMESPACE.length() - 1);
134
135        final String absPath = forward.convert(path);
136
137        if (absPath.isEmpty()) {
138            return "/";
139        }
140        return absPath;
141    }
142
143}