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.camel.component.kafka.transform;
  
  import java.util.*;
  import java.util.stream.Collectors;
  
  import com.fasterxml.jackson.core.type.TypeReference;
  import com.fasterxml.jackson.databind.JsonNode;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import org.apache.camel.Exchange;
  import org.apache.camel.ExchangeProperty;
  import org.apache.camel.InvalidPayloadException;
  import org.apache.camel.util.ObjectHelper;
  
  public class ValueToKey {
  
      public void process(@ExchangeProperty("fields") String fields, Exchange ex) throws InvalidPayloadException {
          List<String> splittedFields = new ArrayList<>();
          ObjectMapper mapper = new ObjectMapper();
          JsonNode jsonNodeBody = ex.getMessage().getBody(JsonNode.class);
          Map<Object, Object> body = mapper.convertValue(jsonNodeBody, new TypeReference<Map<Object, Object>>() {
          });
          if (ObjectHelper.isNotEmpty(fields)) {
              splittedFields = Arrays.stream(fields.split(",")).collect(Collectors.toList());
          }
          Map<Object, Object> key = new HashMap<>();
          for (Map.Entry<Object, Object> entry : body.entrySet()) {
              final String fieldName = (String) entry.getKey();
              if (filterNames(fieldName, splittedFields)) {
                  final Object fieldValue = entry.getValue();
                  key.put(entry.getKey(), fieldValue);
              }
          }
  
          ex.getMessage().setHeader("kafka.KEY", key);
      }
  
      boolean filterNames(String fieldName, List<String> splittedFields) {
          return splittedFields.contains(fieldName);
      }
  }
  