001/*
002 * Licensed to DuraSpace under one or more contributor license agreements.
003 * See the NOTICE file distributed with this work for additional information
004 * regarding copyright ownership.
005 *
006 * DuraSpace licenses this file to you under the Apache License,
007 * Version 2.0 (the "License"); you may not use this file except in
008 * compliance with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.fcrepo.event.serialization;
019
020import static com.fasterxml.jackson.databind.SerializationFeature.WRITE_DATES_AS_TIMESTAMPS;
021import static org.fcrepo.event.serialization.JsonLDEventMessage.from;
022import static org.slf4j.LoggerFactory.getLogger;
023
024import com.fasterxml.jackson.core.JsonProcessingException;
025import com.fasterxml.jackson.databind.ObjectMapper;
026import com.fasterxml.jackson.datatype.jsr310.JSR310Module;
027import org.fcrepo.kernel.api.observer.FedoraEvent;
028import org.slf4j.Logger;
029
030/**
031 * Some serialization utilities for FedoraEvent objects
032 * @author acoburn
033 */
034public class JsonLDSerializer implements EventSerializer {
035
036    private static final Logger LOGGER = getLogger(JsonLDSerializer.class);
037
038    private static final ObjectMapper MAPPER = new ObjectMapper();
039
040    /**
041     * Create a new JSON-LD Event Serializer
042     */
043    public JsonLDSerializer() {
044        // newer versions of jackson rename this to `JavaTimeModule`
045        MAPPER.registerModule(new JSR310Module());
046        MAPPER.configure(WRITE_DATES_AS_TIMESTAMPS, false);
047    }
048
049    /**
050     * Serialize a FedoraEvent into a JSON String
051     * @param evt the Fedora event
052     * @return a JSON string
053     */
054    @Override
055    public String serialize(final FedoraEvent evt) {
056        try {
057            return MAPPER.writeValueAsString(from(evt));
058        } catch (final JsonProcessingException ex) {
059            LOGGER.error("Error processing JSON: {}", ex.getMessage());
060            return null;
061        }
062    }
063}