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.coordinator.common.runtime;
  
  import org.apache.kafka.common.requests.TransactionResult;
  import org.apache.kafka.image.MetadataDelta;
  import org.apache.kafka.image.MetadataImage;
  
  /**
   * CoordinatorShard is basically a replicated state machine managed by the
   * {@link CoordinatorRuntime}.
   */
  public interface CoordinatorShard<U> {
  
      /**
       * The coordinator has been loaded. This is used to apply any
       * post loading operations (e.g. registering timers).
       *
       * @param newImage  The metadata image.
       */
      default void onLoaded(MetadataImage newImage) {}
  
      /**
       * A new metadata image is available. This is only called after {@link CoordinatorShard#onLoaded(MetadataImage)}
       * is called to signal that the coordinator has been fully loaded.
       *
       * @param newImage  The new metadata image.
       * @param delta     The delta image.
       */
      default void onNewMetadataImage(MetadataImage newImage, MetadataDelta delta) {}
  
      /**
       * The coordinator has been unloaded. This is used to apply
       * any post unloading operations.
       */
      default void onUnloaded() {}
  
      /**
       * Replay a record to update the state machine.
       *
       * @param offset        The offset of the record in the log.
       * @param producerId    The producer id.
       * @param producerEpoch The producer epoch.
       * @param record        The record to replay.
       */
      void replay(
          long offset,
          long producerId,
          short producerEpoch,
          U record
      ) throws RuntimeException;
  
      /**
       * Applies the end transaction marker.
       *
       * @param producerId    The producer id.
       * @param producerEpoch The producer epoch.
       * @param result        The result of the transaction.
       * @throws RuntimeException if the transaction can not be completed.
       */
      default void replayEndTransactionMarker(
          long producerId,
          short producerEpoch,
          TransactionResult result
      ) throws RuntimeException {}
  }
  