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;
  
  import java.nio.charset.StandardCharsets;
  import java.util.Map;
  
  import org.apache.camel.Exchange;
  import org.apache.camel.Processor;
  import org.apache.camel.TypeConverter;
  import org.apache.camel.support.SimpleTypeConverter;
  
  /**
   * Header deserializer used in Kafka source Kamelet. Automatically converts all message headers to String. Uses given
   * type converter implementation set on the Camel context to convert values. If no type converter is set the
   * deserializer uses its own fallback conversion implementation.
   */
  public class KafkaHeaderDeserializer implements Processor {
  
      public boolean enabled = false;
  
      private final SimpleTypeConverter defaultTypeConverter = new SimpleTypeConverter(true, KafkaHeaderDeserializer::convert);
  
      @Override
      public void process(Exchange exchange) throws Exception {
          if (!enabled) {
              return;
          }
  
          Map<String, Object> headers = exchange.getMessage().getHeaders();
  
          TypeConverter typeConverter = exchange.getContext().getTypeConverter();
          if (typeConverter == null) {
              typeConverter = defaultTypeConverter;
          }
  
          for (Map.Entry<String, Object> header : headers.entrySet()) {
              if (shouldDeserialize(header)) {
                  header.setValue(typeConverter.convertTo(String.class, header.getValue()));
              }
          }
      }
  
      /**
       * Fallback conversion strategy supporting null values, String and byte[]. Converts headers to respective String
       * representation or null.
       *
       * @param  type     target type, always String in this case.
       * @param  exchange the exchange containing all headers to convert.
       * @param  value    the current value to convert.
       * @return          String representation of given value or null if value itself is null.
       */
      private static Object convert(Class<?> type, Exchange exchange, Object value) {
          if (value == null) {
              return null;
          }
  
          if (value instanceof String) {
              return value;
          }
  
          if (value instanceof byte[]) {
              return new String((byte[]) value, StandardCharsets.UTF_8);
          }
  
          return value.toString();
      }
  
      /**
       * Exclude special Kafka headers from auto deserialization.
       */
      private boolean shouldDeserialize(Map.Entry<String, Object> entry) {
          return !entry.getKey().equals("kafka.HEADERS") && !entry.getKey().equals("CamelKafkaManualCommit");
      }
  
      public void setEnabled(String enabled) {
          this.enabled = Boolean.parseBoolean(enabled);
      }
  }
  