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.transforms;
  
  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.connector.ConnectRecord;
  import org.apache.kafka.connect.header.ConnectHeaders;
  import org.apache.kafka.connect.header.Header;
  import org.apache.kafka.connect.header.Headers;
  import org.apache.kafka.connect.transforms.util.NonEmptyListValidator;
  import org.apache.kafka.connect.transforms.util.SimpleConfig;
  
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  import static org.apache.kafka.common.config.ConfigDef.NO_DEFAULT_VALUE;
  
  public class DropHeaders<R extends ConnectRecord<R>> implements Transformation<R>, Versioned {
  
      public static final String OVERVIEW_DOC =
              "Removes one or more headers from each record.";
  
      public static final String HEADERS_FIELD = "headers";
  
      public static final ConfigDef CONFIG_DEF = new ConfigDef()
              .define(HEADERS_FIELD, ConfigDef.Type.LIST,
                      NO_DEFAULT_VALUE, new NonEmptyListValidator(),
                      ConfigDef.Importance.HIGH,
                      "The name of the headers to be removed.");
  
      private Set<String> headers;
  
      @Override
      public R apply(R record) {
          Headers updatedHeaders = new ConnectHeaders();
          for (Header header : record.headers()) {
              if (!headers.contains(header.key())) {
                  updatedHeaders.add(header);
              }
          }
          return record.newRecord(record.topic(), record.kafkaPartition(), record.keySchema(), record.key(),
                  record.valueSchema(), record.value(), record.timestamp(), updatedHeaders);
      }
  
      @Override
      public String version() {
          return AppInfoParser.getVersion();
      }
  
      @Override
      public ConfigDef config() {
          return CONFIG_DEF;
      }
  
      @Override
      public void close() {
      }
  
      @Override
      public void configure(Map<String, ?> props) {
          final SimpleConfig config = new SimpleConfig(CONFIG_DEF, props);
          headers = new HashSet<>(config.getList(HEADERS_FIELD));
      }
  }
  