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.kafka.connect.runtime;
  
  import org.apache.kafka.common.header.Header;
  import org.apache.kafka.common.header.Headers;
  import org.apache.kafka.common.utils.AppInfoParser;
  import org.apache.kafka.connect.components.Versioned;
  import org.apache.kafka.connect.data.Schema;
  import org.apache.kafka.connect.data.SchemaAndValue;
  import org.apache.kafka.connect.errors.DataException;
  import org.apache.kafka.connect.storage.Converter;
  
  import java.io.UnsupportedEncodingException;
  import java.util.Map;
  
  /**
   * This is a simple Converter implementation that uses "encoding" header to encode/decode strings via provided charset name
   */
  public class SampleConverterWithHeaders implements Converter, Versioned {
      private static final String HEADER_ENCODING = "encoding";
  
      @Override
      public String version() {
          return AppInfoParser.getVersion();
      }
  
      @Override
      public void configure(Map<String, ?> configs, boolean isKey) {
  
      }
  
      @Override
      public SchemaAndValue toConnectData(String topic, Headers headers, byte[] value) {
          String encoding = extractEncoding(headers);
  
          try {
              return new SchemaAndValue(Schema.STRING_SCHEMA, new String(value, encoding));
          } catch (UnsupportedEncodingException e) {
              throw new DataException("Unsupported encoding: " + encoding, e);
          }
      }
  
      @Override
      public byte[] fromConnectData(String topic, Headers headers, Schema schema, Object value) {
          String encoding = extractEncoding(headers);
  
          try {
              return ((String) value).getBytes(encoding);
          } catch (UnsupportedEncodingException e) {
              throw new DataException("Unsupported encoding: " + encoding, e);
          }
      }
  
      private String extractEncoding(Headers headers) {
          Header header = headers.lastHeader(HEADER_ENCODING);
          if (header == null) {
              throw new DataException("Header '" + HEADER_ENCODING + "' is required!");
          }
  
          return new String(header.value());
      }
  
  
      @Override
      public SchemaAndValue toConnectData(String topic, byte[] value) {
          throw new DataException("Headers are required for this converter!");
      }
  
      @Override
      public byte[] fromConnectData(String topic, Schema schema, Object value) {
          throw new DataException("Headers are required for this converter!");
      }
  }
  