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.errors.SerializationException;
  import org.apache.kafka.common.serialization.StringDeserializer;
  import org.apache.kafka.common.serialization.StringSerializer;
  import org.apache.kafka.common.utils.AppInfoParser;
  import org.apache.kafka.common.utils.Utils;
  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 java.util.HashMap;
  import java.util.Map;
  
  /**
   * {@link Converter} and {@link HeaderConverter} implementation that only supports serializing to strings. When converting Kafka Connect
   * data to bytes, the schema will be ignored and {@link Object#toString()} will always be invoked to convert the data to a String.
   * When converting from bytes to Kafka Connect format, the converter will only ever return an optional string schema and
   * a string or null.
   * <p>
   * Encoding configuration is identical to {@link StringSerializer} and {@link StringDeserializer}, but for convenience
   * this class can also be configured to use the same encoding for both encoding and decoding with the
   * {@link StringConverterConfig#ENCODING_CONFIG converter.encoding} setting.
   * <p>
   * This implementation currently does nothing with the topic names or header keys.
   */
  public class StringConverter implements Converter, HeaderConverter, Versioned {
  
      private final StringSerializer serializer = new StringSerializer();
      private final StringDeserializer deserializer = new StringDeserializer();
  
      public StringConverter() {
      }
  
      @Override
      public String version() {
          return AppInfoParser.getVersion();
      }
  
      @Override
      public ConfigDef config() {
          return StringConverterConfig.configDef();
      }
  
      @Override
      public void configure(Map<String, ?> configs) {
          StringConverterConfig conf = new StringConverterConfig(configs);
          String encoding = conf.encoding();
  
          Map<String, Object> serializerConfigs = new HashMap<>(configs);
          Map<String, Object> deserializerConfigs = new HashMap<>(configs);
          serializerConfigs.put("serializer.encoding", encoding);
          deserializerConfigs.put("deserializer.encoding", encoding);
  
          boolean isKey = conf.type() == ConverterType.KEY;
          serializer.configure(serializerConfigs, isKey);
          deserializer.configure(deserializerConfigs, isKey);
      }
  
      @Override
      public void configure(Map<String, ?> configs, boolean isKey) {
          Map<String, Object> conf = new HashMap<>(configs);
          conf.put(StringConverterConfig.TYPE_CONFIG, isKey ? ConverterType.KEY.getName() : ConverterType.VALUE.getName());
          configure(conf);
      }
  
      @Override
      public byte[] fromConnectData(String topic, Schema schema, Object value) {
          try {
              return serializer.serialize(topic, value == null ? null : value.toString());
          } catch (SerializationException e) {
              throw new DataException("Failed to serialize to a string: ", e);
          }
      }
  
      @Override
      public SchemaAndValue toConnectData(String topic, byte[] value) {
          try {
              return new SchemaAndValue(Schema.OPTIONAL_STRING_SCHEMA, deserializer.deserialize(topic, value));
          } catch (SerializationException e) {
              throw new DataException("Failed to deserialize string: ", e);
          }
      }
  
      @Override
      public byte[] fromConnectHeader(String topic, String headerKey, Schema schema, Object value) {
          return fromConnectData(topic, schema, value);
      }
  
      @Override
      public SchemaAndValue toConnectHeader(String topic, String headerKey, byte[] value) {
          return toConnectData(topic, value);
      }
  
      @Override
      public void close() {
          Utils.closeQuietly(this.serializer, "string converter serializer");
          Utils.closeQuietly(this.deserializer, "string converter deserializer");
      }
  }
  