edu.amherst.acdc.idiomatic.EventRouter Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of acrepo-idiomatic Show documentation
Camel-based service for mapping public IDs to Fedora IDs
The newest version!
/**
 * Copyright 2015 Amherst College
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package edu.amherst.acdc.idiomatic;

import static org.apache.camel.builder.PredicateBuilder.not;
import static edu.amherst.acdc.idiomatic.IdiomaticHeaders.FEDORA;
import static edu.amherst.acdc.idiomatic.IdiomaticHeaders.ID;

import org.apache.camel.Exchange;
import org.apache.camel.LoggingLevel;
import org.apache.camel.Processor;
import org.apache.camel.PropertyInject;
import org.apache.camel.RuntimeCamelException;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.builder.xml.Namespaces;

/**
 * A content router for handling JMS events.
 *
 * @author Aaron Coburn
 */
public class EventRouter extends RouteBuilder {

    @PropertyInject(value = "rest.port", defaultValue = "9081")
    private String port;

    /**
     * Configure the message route workflow.
     */
    public void configure() throws Exception {

        final String idPrefix;
        final Namespaces ns = new Namespaces("rdf", "http://www.w3.org/1999/02/22-rdf-syntax-ns#");

        try {
            idPrefix = getContext().resolvePropertyPlaceholders("{{id.prefix}}");
            final String property = getContext().resolvePropertyPlaceholders("{{id.property}}");
            final String namespace = getContext().resolvePropertyPlaceholders("{{id.namespace}}");
            final String prefix = property.substring(0, property.indexOf(":"));
            ns.add(prefix, namespace);

        } catch (final Exception ex) {
            throw new RuntimeCamelException("Could not resolve property placeholders", ex);
        }

        /**
         * A generic error handler (specific to this RouteBuilder)
         */
        onException(Exception.class)
            .maximumRedeliveries("{{error.maxRedeliveries}}")
            .log("Event Routing Error: ${routeId}");

        /**
         * Process a message via JMS
         */
        from("{{input.stream}}")
            .routeId("IdMappingRouter")
            .to("direct:event");

        from("direct:event")
            .routeId("IdMappingEventRouter")
            .log(LoggingLevel.INFO, "IdMapping Event: ${headers[org.fcrepo.jms.identifier]}")
            .to("fcrepo:{{fcrepo.baseUrl}}?preferOmit=PreferContainment")
            .split().xtokenize("//{{id.property}}", 'i', ns)
              .setHeader(ID).xpath("/{{id.property}}/@rdf:resource | /{{id.property}}/text()", String.class, ns)
              .process(new Processor() {
                  public void process(final Exchange ex) throws Exception {
                      ex.getIn().setHeader(ID, ex.getIn().getHeader(ID, String.class).replaceAll("^" + idPrefix, ""));
                  }})
              .transform().simple("${header[org.fcrepo.jms.identifier]}")
              .to("direct:update");

        /**
         * REST routing
         */
        rest("{{rest.prefix}}")
            .get("/{" + ID + "}").to("direct:get")
            .post("/").to("direct:minter")
            .put("/{" + ID + "}").to("direct:update")
            .delete("/{" + ID + "}").to("direct:delete");

        /**
         * Handle CRUD operations
         */
        from("direct:update")
            .routeId("IdMappingUpdateRouter")
            .setHeader(FEDORA).simple("${body}")
            .setHeader(Exchange.HTTP_RESPONSE_CODE).constant(400)
            .filter(header(FEDORA))
              .log(LoggingLevel.INFO, "Updating ${headers[" + ID + "]} with ${headers[" + FEDORA + "]}")
              .to("sql:UPDATE uris SET fedora=:#" + FEDORA + " WHERE public=:#" + ID)
              .setHeader(Exchange.HTTP_RESPONSE_CODE).constant(204)
              .choice()
                .when(header("CamelSqlUpdateCount").isEqualTo("0"))
                  .to("sql:INSERT INTO uris (fedora, public) VALUES (:#" + FEDORA + ", :#" + ID + ")").end()
            .removeHeader(ID)
            .removeHeader(FEDORA);

        from("direct:get")
            .routeId("IdMappingFetchRouter")
            .to("sql:SELECT fedora FROM uris WHERE public=:#" + ID + "?outputType=SelectOne")
            .removeHeader(ID)
            .filter(not(header("CamelSqlRowCount").isEqualTo(1)))
                .setHeader(Exchange.HTTP_RESPONSE_CODE).constant(404);

        from("direct:delete")
            .routeId("IdMappingDeleteRouter")
            .log(LoggingLevel.INFO, "Deleting ${headers[" + ID + "]}")
            .to("sql:DELETE FROM uris WHERE public=:#" + ID)
            .removeHeader(ID)
            .setHeader(Exchange.HTTP_RESPONSE_CODE).constant(204);

    }
}