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.metadata.publisher;
  
  import org.apache.kafka.common.utils.LogContext;
  import org.apache.kafka.image.MetadataDelta;
  import org.apache.kafka.image.MetadataImage;
  import org.apache.kafka.image.loader.LoaderManifest;
  import org.apache.kafka.image.publisher.MetadataPublisher;
  import org.apache.kafka.server.common.FinalizedFeatures;
  
  import org.slf4j.Logger;
  
  import static org.apache.kafka.server.common.MetadataVersion.MINIMUM_VERSION;
  
  
  public class FeaturesPublisher implements MetadataPublisher {
      private final Logger log;
      private volatile FinalizedFeatures finalizedFeatures = FinalizedFeatures.fromKRaftVersion(MINIMUM_VERSION);
  
      public FeaturesPublisher(
          LogContext logContext
      ) {
          log = logContext.logger(FeaturesPublisher.class);
      }
  
      public FinalizedFeatures features() {
          return finalizedFeatures;
      }
  
      @Override
      public String name() {
          return "FeaturesPublisher";
      }
  
      @Override
      public void onMetadataUpdate(
          MetadataDelta delta,
          MetadataImage newImage,
          LoaderManifest manifest
      ) {
          if (delta.featuresDelta() != null) {
              FinalizedFeatures newFinalizedFeatures = new FinalizedFeatures(newImage.features().metadataVersionOrThrow(),
                      newImage.features().finalizedVersions(),
                      newImage.provenance().lastContainedOffset()
              );
              if (!newFinalizedFeatures.equals(finalizedFeatures)) {
                  log.info("Loaded new metadata {}.", newFinalizedFeatures);
                  finalizedFeatures = newFinalizedFeatures;
              }
          }
      }
  }
  