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.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    /**
046     * Configure the message route workflow.
047     */
048    public void configure() throws Exception {
049
050        final Namespaces ns = new Namespaces("rdf", RDF);
051        ns.add("indexing", INDEXING);
052
053        final XPathBuilder indexable = new XPathBuilder(
054                String.format("/rdf:RDF/rdf:Description/rdf:type[@rdf:resource='%s']", INDEXING + "Indexable"));
055        indexable.namespaces(ns);
056
057        /**
058         * A generic error handler (specific to this RouteBuilder)
059         */
060        onException(Exception.class)
061            .maximumRedeliveries("{{error.maxRedeliveries}}")
062            .log("Index Routing Error: ${routeId}");
063
064        /**
065         * route a message to the proper queue, based on whether
066         * it is a DELETE or UPDATE operation.
067         */
068        from("{{input.stream}}")
069            .routeId("FcrepoTriplestoreRouter")
070            .choice()
071                .when(header(EVENT_TYPE).isEqualTo(REPOSITORY + "NODE_REMOVED"))
072                    .to("direct:delete.triplestore")
073                .otherwise()
074                    .to("direct:index.triplestore");
075
076        /**
077         * Handle re-index events
078         */
079        from("{{triplestore.reindex.stream}}")
080            .routeId("FcrepoTriplestoreReindex")
081            .to("direct:index.triplestore");
082
083        /**
084         * Based on an item's metadata, determine if it is indexable.
085         */
086        from("direct:index.triplestore")
087            .routeId("FcrepoTriplestoreIndexer")
088            .filter(not(or(header(IDENTIFIER).startsWith(simple("{{audit.container}}/")),
089                    header(IDENTIFIER).isEqualTo(simple("{{audit.container}}")))))
090            .removeHeaders("CamelHttp*")
091            .to("fcrepo:{{fcrepo.baseUrl}}?preferInclude=PreferMinimalContainer&accept=application/rdf+xml")
092            .choice()
093                .when(or(simple("{{indexing.predicate}} != 'true'"), indexable))
094                    .to("direct:update.triplestore")
095                .otherwise()
096                    .to("direct:delete.triplestore");
097
098        /**
099         * Remove an item from the triplestore index.
100         */
101        from("direct:delete.triplestore")
102            .routeId("FcrepoTriplestoreDeleter")
103            .process(new SparqlDeleteProcessor())
104            .log(LoggingLevel.INFO, logger,
105                    "Deleting Triplestore Object ${headers[CamelFcrepoIdentifier]} " +
106                    "${headers[org.fcrepo.jms.identifier]}")
107            .to("http4://{{triplestore.baseUrl}}");
108
109        /**
110         * Perform the sparql update.
111         */
112        from("direct:update.triplestore")
113            .routeId("FcrepoTriplestoreUpdater")
114            .setHeader(FCREPO_NAMED_GRAPH)
115                .simple("{{triplestore.namedGraph}}")
116            .to("fcrepo:{{fcrepo.baseUrl}}?accept=application/n-triples" +
117                    "&preferOmit={{prefer.omit}}&preferInclude={{prefer.include}}")
118            .process(new SparqlUpdateProcessor())
119            .log(LoggingLevel.INFO, logger,
120                    "Indexing Triplestore Object ${headers[CamelFcrepoIdentifier]} " +
121                    "${headers[org.fcrepo.jms.identifier]}")
122            .to("http4://{{triplestore.baseUrl}}");
123    }
124}