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.storage;
  
  import org.apache.kafka.common.config.ConfigDef;
  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.data.Values;
  import org.apache.kafka.connect.errors.DataException;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.nio.charset.StandardCharsets;
  import java.util.Map;
  import java.util.NoSuchElementException;
  
  /**
   * A {@link HeaderConverter} that serializes header values as strings and that deserializes header values to the most appropriate
   * numeric, boolean, array, or map representation. Schemas are not serialized, but are inferred upon deserialization when possible.
   */
  public class SimpleHeaderConverter implements HeaderConverter, Versioned {
  
      private static final Logger LOG = LoggerFactory.getLogger(SimpleHeaderConverter.class);
      private static final ConfigDef CONFIG_DEF = new ConfigDef();
      private static final SchemaAndValue NULL_SCHEMA_AND_VALUE = new SchemaAndValue(null, null);
      private static final Charset UTF_8 = StandardCharsets.UTF_8;
  
      @Override
      public String version() {
          return AppInfoParser.getVersion();
      }
  
      @Override
      public ConfigDef config() {
          return CONFIG_DEF;
      }
  
      @Override
      public void configure(Map<String, ?> configs) {
          // do nothing
      }
  
      @Override
      public SchemaAndValue toConnectHeader(String topic, String headerKey, byte[] value) {
          if (value == null) {
              return NULL_SCHEMA_AND_VALUE;
          }
          try {
              String str = new String(value, UTF_8);
              return Values.parseString(str);
          } catch (NoSuchElementException e) {
              throw new DataException("Failed to deserialize value for header '" + headerKey + "' on topic '" + topic + "'", e);
          } catch (Throwable t) {
              LOG.warn("Failed to deserialize value for header '{}' on topic '{}', so using byte array", headerKey, topic, t);
              return new SchemaAndValue(Schema.BYTES_SCHEMA, value);
          }
      }
  
      @Override
      public byte[] fromConnectHeader(String topic, String headerKey, Schema schema, Object value) {
          if (value == null) {
              return null;
          }
          return Values.convertToString(schema, value).getBytes(UTF_8);
      }
  
      @Override
      public void close() throws IOException {
          // do nothing
      }
  }
  