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.snapshot;
  
  import org.apache.kafka.common.message.SnapshotFooterRecord;
  import org.apache.kafka.server.common.OffsetAndEpoch;
  
  import java.util.List;
  
  /**
   * A type for writing a snapshot for a given end offset and epoch.
   *
   * A snapshot writer can be used to append objects until freeze is called. When freeze is
   * called the snapshot is validated and marked as immutable. After freeze is called any
   * append will fail with an exception.
   *
   * It is assumed that the content of the snapshot represents all the records for the
   * topic partition from offset 0 up to but not including the end offset in the snapshot
   * id.
   *
   * @see org.apache.kafka.raft.RaftClient#createSnapshot(OffsetAndEpoch, long)
   */
  public interface SnapshotWriter<T> extends AutoCloseable {
      /**
       * Returns the end offset and epoch for the snapshot.
       */
      OffsetAndEpoch snapshotId();
  
      /**
       * Returns the last log offset which is represented in the snapshot.
       */
      long lastContainedLogOffset();
  
      /**
       * Returns the epoch of the last log offset which is represented in the snapshot.
       */
      int lastContainedLogEpoch();
  
      /**
       * Returns true if the snapshot has been frozen, otherwise false is returned.
       *
       * Modification to the snapshot are not allowed once it is frozen.
       */
      boolean isFrozen();
  
      /**
       * Appends a list of values to the snapshot.
       *
       * The list of record passed are guaranteed to get written together.
       *
       * @param records the list of records to append to the snapshot
       * @throws IllegalStateException if append is called when isFrozen is true
       */
      void append(List<T> records);
  
      /**
       * Freezes the snapshot by flushing all pending writes and marking it as immutable.
       *
       * Also adds a {@link SnapshotFooterRecord} to the end of the snapshot
       *
       * @return  The size of the snapshot in bytes.
       */
      long freeze();
  
      /**
       * Closes the snapshot writer.
       *
       * If close is called without first calling freeze the snapshot is aborted.
       */
      void close();
  
  }
  