trunk/clients/csharp/src/Kafka/Kafka.Client/Request/MultiFetchRequest.cs

/**
 * 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.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Kafka.Client.Util;

namespace Kafka.Client.Request
{
    /// <summary>
    /// Constructs a multi-consumer request to send to Kafka.
    /// </summary>
    public class MultiFetchRequest : AbstractRequest
    {
        /// <summary>
        /// Initializes a new instance of the MultiFetchRequest class.
        /// </summary>
        /// <param name="requests">Requests to package up and batch.</param>
        public MultiFetchRequest(IList<FetchRequest> requests)
        {
            ConsumerRequests = requests;
        }

        /// <summary>
        /// Gets or sets the consumer requests to be batched into this multi-request.
        /// </summary>
        public IList<FetchRequest> ConsumerRequests { get; set; }

        /// <summary>
        /// Determines if the request has valid settings.
        /// </summary>
        /// <returns>True if valid and false otherwise.</returns>
        public override bool IsValid()
        {
            return ConsumerRequests != null && ConsumerRequests.Count > 0
                && ConsumerRequests.Select(itm => !itm.IsValid()).Count() > 0;
        }

        /// <summary>
        /// Gets the bytes matching the expected Kafka structure. 
        /// </summary>
        /// <returns>The byte array of the request.</returns>
        public override byte[] GetBytes()
        {
            List<byte> messagePack = new List<byte>();
            byte[] requestBytes = BitWorks.GetBytesReversed(Convert.ToInt16((int)RequestType.MultiFetch));
            byte[] consumerRequestCountBytes = BitWorks.GetBytesReversed(Convert.ToInt16(ConsumerRequests.Count));

            List<byte> encodedMessageSet = new List<byte>();
            encodedMessageSet.AddRange(requestBytes);
            encodedMessageSet.AddRange(consumerRequestCountBytes);

            foreach (FetchRequest consumerRequest in ConsumerRequests)
            {
                encodedMessageSet.AddRange(consumerRequest.GetInternalBytes());
            }

            encodedMessageSet.InsertRange(0, BitWorks.GetBytesReversed(encodedMessageSet.Count));

            return encodedMessageSet.ToArray();
        }
    }
}