content: /*
   * Copyright 2014-2025 Real Logic Limited.
   *
   * Licensed 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
   *
   * https://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 io.aeron.command;
  
  import io.aeron.exceptions.ControlProtocolException;
  import org.agrona.MutableDirectBuffer;
  
  import static io.aeron.ErrorCode.MALFORMED_COMMAND;
  import static org.agrona.BitUtil.SIZE_OF_LONG;
  
  /**
   * Base flyweight that can be extended to track a client request.
   * <p>
   * 0                   1                   2                   3
   * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                         Client ID                             |
   * |                                                               |
   * +---------------------------------------------------------------+
   * |                       Correlation ID                          |
   * |                                                               |
   * +---------------------------------------------------------------+
   */
  public class CorrelatedMessageFlyweight
  {
      /**
       * Length of the header.
       */
      public static final int LENGTH = 2 * SIZE_OF_LONG;
      private static final int CLIENT_ID_FIELD_OFFSET = 0;
      static final int CORRELATION_ID_FIELD_OFFSET = CLIENT_ID_FIELD_OFFSET + SIZE_OF_LONG;
  
      MutableDirectBuffer buffer;
      int offset;
  
      /**
       * Wrap the buffer at a given offset for updates.
       *
       * @param buffer to wrap.
       * @param offset at which the message begins.
       * @return this for a fluent API.
       */
      public CorrelatedMessageFlyweight wrap(final MutableDirectBuffer buffer, final int offset)
      {
          this.buffer = buffer;
          this.offset = offset;
  
          return this;
      }
  
      /**
       * Get client id field.
       *
       * @return client id field.
       */
      public long clientId()
      {
          return buffer.getLong(offset + CLIENT_ID_FIELD_OFFSET);
      }
  
      /**
       * Set client id field.
       *
       * @param clientId field value.
       * @return this for a fluent API.
       */
      public CorrelatedMessageFlyweight clientId(final long clientId)
      {
          buffer.putLong(offset + CLIENT_ID_FIELD_OFFSET, clientId);
  
          return this;
      }
  
      /**
       * Get correlation id field.
       *
       * @return correlation id field.
       */
      public long correlationId()
      {
          return buffer.getLong(offset + CORRELATION_ID_FIELD_OFFSET);
      }
  
      /**
       * Set correlation id field.
       *
       * @param correlationId field value.
       * @return this for a fluent API.
       */
      public CorrelatedMessageFlyweight correlationId(final long correlationId)
      {
          buffer.putLong(offset + CORRELATION_ID_FIELD_OFFSET, correlationId);
  
          return this;
      }
  
      /**
       * Validate buffer length is long enough for message.
       *
       * @param msgTypeId type of message.
       * @param length of message in bytes to validate.
       */
      public void validateLength(final int msgTypeId, final int length)
      {
          if (length < LENGTH)
          {
              throw new ControlProtocolException(
                  MALFORMED_COMMAND, "command=" + msgTypeId + " too short: length=" + length);
          }
      }
  }
  