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.common.record;
  
  import org.apache.kafka.common.InvalidRecordException;
  import org.apache.kafka.common.message.EndTxnMarker;
  import org.apache.kafka.common.protocol.ByteBufferAccessor;
  import org.apache.kafka.common.protocol.MessageUtil;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.nio.ByteBuffer;
  
  /**
   * This class represents the control record which is written to the log to indicate the completion
   * of a transaction. The record key specifies the {@link ControlRecordType control type} and the
   * value embeds information useful for write validation (for now, just the coordinator epoch).
   */
  public class EndTransactionMarker {
      private static final Logger log = LoggerFactory.getLogger(EndTransactionMarker.class);
  
      private final ControlRecordType type;
      private final int coordinatorEpoch;
      private final ByteBuffer buffer;
  
      public EndTransactionMarker(ControlRecordType type, int coordinatorEpoch) {
          ensureTransactionMarkerControlType(type);
          this.type = type;
          this.coordinatorEpoch = coordinatorEpoch;
          EndTxnMarker marker = new EndTxnMarker().setCoordinatorEpoch(coordinatorEpoch);
          this.buffer = MessageUtil.toVersionPrefixedByteBuffer(EndTxnMarker.HIGHEST_SUPPORTED_VERSION, marker);
      }
  
      public int coordinatorEpoch() {
          return coordinatorEpoch;
      }
  
      public ControlRecordType controlType() {
          return type;
      }
  
      public ByteBuffer serializeValue() {
          return buffer.duplicate();
      }
  
      @Override
      public boolean equals(Object o) {
          if (this == o) return true;
          if (o == null || getClass() != o.getClass()) return false;
  
          EndTransactionMarker that = (EndTransactionMarker) o;
          return coordinatorEpoch == that.coordinatorEpoch && type == that.type;
      }
  
      @Override
      public int hashCode() {
          int result = type != null ? type.hashCode() : 0;
          result = 31 * result + coordinatorEpoch;
          return result;
      }
  
      private static void ensureTransactionMarkerControlType(ControlRecordType type) {
          if (type != ControlRecordType.COMMIT && type != ControlRecordType.ABORT)
              throw new IllegalArgumentException("Invalid control record type for end transaction marker " + type);
      }
  
      public static EndTransactionMarker deserialize(Record record) {
          ControlRecordType type = ControlRecordType.parse(record.key());
          return deserializeValue(type, record.value());
      }
  
      // Visible for testing
      static EndTransactionMarker deserializeValue(ControlRecordType type, ByteBuffer value) {
          ensureTransactionMarkerControlType(type);
  
          short version = value.getShort();
          if (version < EndTxnMarker.LOWEST_SUPPORTED_VERSION)
              throw new InvalidRecordException("Invalid version found for end transaction marker: " + version +
                      ". May indicate data corruption");
  
          if (version > EndTxnMarker.HIGHEST_SUPPORTED_VERSION) {
              log.debug("Received end transaction marker value version {}. Parsing as version {}", version,
                      EndTxnMarker.HIGHEST_SUPPORTED_VERSION);
              version = EndTxnMarker.HIGHEST_SUPPORTED_VERSION;
          }
          EndTxnMarker marker = new EndTxnMarker(new ByteBufferAccessor(value), version);
          return new EndTransactionMarker(type, marker.coordinatorEpoch());
      }
  
      public int endTxnMarkerValueSize() {
          return DefaultRecord.sizeInBytes(0, 0L,
                  ControlRecordType.CURRENT_CONTROL_RECORD_KEY_SIZE,
                  buffer.remaining(),
                  Record.EMPTY_HEADERS);
      }
  
  }
  