lang/cs/Org.Apache.REEF.IMRU/OnREEF/IMRUTasks/MapTaskHost.cs

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// 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
// 
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// software distributed under the License is distributed on an
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using System;
using Org.Apache.REEF.Common.Tasks;
using Org.Apache.REEF.IMRU.API;
using Org.Apache.REEF.IMRU.OnREEF.Driver;
using Org.Apache.REEF.IMRU.OnREEF.MapInputWithControlMessage;
using Org.Apache.REEF.IMRU.OnREEF.Parameters;
using Org.Apache.REEF.Network.Group.Operators;
using Org.Apache.REEF.Network.Group.Task;
using Org.Apache.REEF.Tang.Annotations;
using Org.Apache.REEF.Utilities.Logging;

namespace Org.Apache.REEF.IMRU.OnREEF.IMRUTasks
{
    /// <summary>
    /// Hosts the IMRU MapTask in a REEF Task.
    /// </summary>
    /// <typeparam name="TMapInput">Map input</typeparam>
    /// <typeparam name="TMapOutput">Map output</typeparam>
    internal sealed class MapTaskHost<TMapInput, TMapOutput> : ITask
    {
        private static readonly Logger Logger = Logger.GetLogger(typeof(MapTaskHost<TMapInput, TMapOutput>));

        private readonly IBroadcastReceiver<MapInputWithControlMessage<TMapInput>> _dataAndMessageReceiver;
        private readonly IReduceSender<TMapOutput> _dataReducer;
        private readonly IMapFunction<TMapInput, TMapOutput> _mapTask;
        private readonly bool _invokeGC;

        /// <summary>
        /// </summary>
        /// <param name="mapTask">The MapTask hosted in this REEF Task.</param>
        /// <param name="groupCommunicationsClient">Used to setup the communications.</param>
        /// <param name="invokeGC">Whether to call Garbage Collector after each iteration or not</param>
        [Inject]
        private MapTaskHost(
            IMapFunction<TMapInput, TMapOutput> mapTask,
            IGroupCommClient groupCommunicationsClient,
            [Parameter(typeof(InvokeGC))] bool invokeGC)
        {
            _mapTask = mapTask;
            var cg = groupCommunicationsClient.GetCommunicationGroup(IMRUConstants.CommunicationGroupName);
            _dataAndMessageReceiver =
                cg.GetBroadcastReceiver<MapInputWithControlMessage<TMapInput>>(IMRUConstants.BroadcastOperatorName);
            _dataReducer = cg.GetReduceSender<TMapOutput>(IMRUConstants.ReduceOperatorName);
            _invokeGC = invokeGC;
        }

        /// <summary>
        /// Performs IMRU iterations on map side
        /// </summary>
        /// <param name="memento"></param>
        /// <returns></returns>
        public byte[] Call(byte[] memento)
        {
            while (true)
            {
                if (_invokeGC)
                {
                    Logger.Log(Level.Verbose, "Calling Garbage Collector");
                    GC.Collect();
                    GC.WaitForPendingFinalizers();
                }

                TMapOutput result;

                using (
                    MapInputWithControlMessage<TMapInput> mapInput = _dataAndMessageReceiver.Receive())
                {
                    if (mapInput.ControlMessage == MapControlMessage.Stop)
                    {
                        break;
                    }
                    result = _mapTask.Map(mapInput.Message);
                }
             
                _dataReducer.Send(result);
            }
            return null;
        }

        /// <summary>
        /// Dispose function 
        /// </summary>
        public void Dispose()
        {
        }
    }
}