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.image.writer;
  
  import org.apache.kafka.server.common.ApiMessageAndVersion;
  import org.apache.kafka.snapshot.SnapshotWriter;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.OptionalLong;
  
  
  /**
   * Writes out a metadata image to a SnapshotWriter.
   */
  public class RaftSnapshotWriter implements ImageWriter {
      private final SnapshotWriter<ApiMessageAndVersion> snapshotWriter;
      private final int batchSize;
      private List<ApiMessageAndVersion> records;
      private OptionalLong frozenSize = OptionalLong.empty();
  
      public RaftSnapshotWriter(
          SnapshotWriter<ApiMessageAndVersion> snapshotWriter,
          int batchSize
      ) {
          this.snapshotWriter = snapshotWriter;
          this.batchSize = batchSize;
          this.records = new ArrayList<>();
      }
  
      @Override
      public void write(ApiMessageAndVersion record) {
          if (records == null) throw new ImageWriterClosedException();
          records.add(record);
          if (records.size() >= batchSize) {
              snapshotWriter.append(records);
              records = new ArrayList<>();
          }
      }
  
      @Override
      public void close(boolean complete) {
          if (records == null) return;
          try {
              if (complete) {
                  if (!records.isEmpty()) {
                      snapshotWriter.append(records);
                  }
                  frozenSize = OptionalLong.of(snapshotWriter.freeze());
              }
          } finally {
              records = null;
              snapshotWriter.close();
          }
      }
  
      /**
       * @return the frozen size of the snapshot, or OptionalLong.empty if the snapshot was not frozen.
       */
      public OptionalLong frozenSize() {
          return frozenSize;
      }
  }
  