001/*
002 * Copyright 2016 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.camel.indexing.triplestore;
017
018import static org.apache.camel.builder.PredicateBuilder.not;
019import static org.apache.camel.builder.PredicateBuilder.or;
020import static org.fcrepo.camel.FcrepoHeaders.FCREPO_NAMED_GRAPH;
021import static org.fcrepo.camel.JmsHeaders.EVENT_TYPE;
022import static org.fcrepo.camel.JmsHeaders.IDENTIFIER;
023import static org.fcrepo.camel.RdfNamespaces.INDEXING;
024import static org.fcrepo.camel.RdfNamespaces.RDF;
025import static org.fcrepo.camel.RdfNamespaces.REPOSITORY;
026import static org.slf4j.LoggerFactory.getLogger;
027
028import org.apache.camel.LoggingLevel;
029import org.apache.camel.builder.RouteBuilder;
030import org.apache.camel.builder.xml.Namespaces;
031import org.apache.camel.builder.xml.XPathBuilder;
032import org.fcrepo.camel.processor.SparqlDeleteProcessor;
033import org.fcrepo.camel.processor.SparqlUpdateProcessor;
034import org.slf4j.Logger;
035
036/**
037 * A content router for handling JMS events.
038 *
039 * @author Aaron Coburn
040 */
041public class TriplestoreRouter extends RouteBuilder {
042
043    private static final Logger logger = getLogger(TriplestoreRouter.class);
044
045    private static final String RESOURCE_DELETION = "http://fedora.info/definitions/v4/event#ResourceDeletion";
046
047    /**
048     * Configure the message route workflow.
049     */
050    public void configure() throws Exception {
051
052        final Namespaces ns = new Namespaces("rdf", RDF);
053        ns.add("indexing", INDEXING);
054
055        final XPathBuilder indexable = new XPathBuilder(
056                String.format("/rdf:RDF/rdf:Description/rdf:type[@rdf:resource='%s']", INDEXING + "Indexable"));
057        indexable.namespaces(ns);
058
059        /**
060         * A generic error handler (specific to this RouteBuilder)
061         */
062        onException(Exception.class)
063            .maximumRedeliveries("{{error.maxRedeliveries}}")
064            .log("Index Routing Error: ${routeId}");
065
066        /**
067         * route a message to the proper queue, based on whether
068         * it is a DELETE or UPDATE operation.
069         */
070        from("{{input.stream}}")
071            .routeId("FcrepoTriplestoreRouter")
072            .choice()
073                // this clause supports Fedora 4.5.1 and earlier but may be removed in a future release
074                .when(header(EVENT_TYPE).isEqualTo(REPOSITORY + "NODE_REMOVED"))
075                    .to("direct:delete.triplestore")
076                .when(header(EVENT_TYPE).isEqualTo(RESOURCE_DELETION))
077                    .to("direct:delete.triplestore")
078                .otherwise()
079                    .to("direct:index.triplestore");
080
081        /**
082         * Handle re-index events
083         */
084        from("{{triplestore.reindex.stream}}")
085            .routeId("FcrepoTriplestoreReindex")
086            .to("direct:index.triplestore");
087
088        /**
089         * Based on an item's metadata, determine if it is indexable.
090         */
091        from("direct:index.triplestore")
092            .routeId("FcrepoTriplestoreIndexer")
093            .filter(not(or(header(IDENTIFIER).startsWith(simple("{{audit.container}}/")),
094                    header(IDENTIFIER).isEqualTo(simple("{{audit.container}}")))))
095            .removeHeaders("CamelHttp*")
096            .to("fcrepo:{{fcrepo.baseUrl}}?preferInclude=PreferMinimalContainer&accept=application/rdf+xml")
097            .choice()
098                .when(or(simple("{{indexing.predicate}} != 'true'"), indexable))
099                    .to("direct:update.triplestore")
100                .otherwise()
101                    .to("direct:delete.triplestore");
102
103        /**
104         * Remove an item from the triplestore index.
105         */
106        from("direct:delete.triplestore")
107            .routeId("FcrepoTriplestoreDeleter")
108            .process(new SparqlDeleteProcessor())
109            .log(LoggingLevel.INFO, logger,
110                    "Deleting Triplestore Object ${headers[CamelFcrepoIdentifier]} " +
111                    "${headers[org.fcrepo.jms.identifier]}")
112            .to("{{triplestore.baseUrl}}?useSystemProperties=true");
113
114        /**
115         * Perform the sparql update.
116         */
117        from("direct:update.triplestore")
118            .routeId("FcrepoTriplestoreUpdater")
119            .setHeader(FCREPO_NAMED_GRAPH)
120                .simple("{{triplestore.namedGraph}}")
121            .to("fcrepo:{{fcrepo.baseUrl}}?accept=application/n-triples" +
122                    "&preferOmit={{prefer.omit}}&preferInclude={{prefer.include}}")
123            .process(new SparqlUpdateProcessor())
124            .log(LoggingLevel.INFO, logger,
125                    "Indexing Triplestore Object ${headers[CamelFcrepoIdentifier]} " +
126                    "${headers[org.fcrepo.jms.identifier]}")
127            .to("{{triplestore.baseUrl}}?useSystemProperties=true");
128    }
129}