content: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.apex.malhar.contrib.enrich;
  
  import java.io.IOException;
  import java.util.Map;
  
  import org.codehaus.jackson.map.ObjectMapper;
  import org.codehaus.jackson.map.ObjectReader;
  import org.codehaus.jackson.type.TypeReference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.hadoop.classification.InterfaceStability;
  
  /**
   * This implementation of {@link FSLoader} is used to load data from json file.
   * <p>
   * The input file needs to have one Json per line. E.g:
   * <p>
   * {"productCategory": 5, "productId": 0}
   * {"productCategory": 4, "productId": 1}
   * {"productCategory": 5, "productId": 2}
   * {"productCategory": 5, "productId": 3}
   * </p>
   * Each line in the input file should be a valid json object which represents a
   * record and each key/value pair in that json object represents the
   * fields/value.
   * <p>
   *
   *
   * @since 3.5.0
   */
  @InterfaceStability.Evolving
  public class JsonFSLoader extends FSLoader
  {
  
    private static final ObjectMapper mapper = new ObjectMapper();
    private static final ObjectReader reader = mapper.reader(new TypeReference<Map<String, Object>>()
    {
    });
  
    private static final Logger logger = LoggerFactory.getLogger(JsonFSLoader.class);
  
    /**
     * Extracts the fields from a json record and returns a map containing field
     * names and values
     */
    @Override
    Map<String, Object> extractFields(String line)
    {
      try {
        return reader.readValue(line);
      } catch (IOException e) {
        logger.error("Exception while extracting fields {}", e);
      }
      return null;
    }
  
  }
  