spark\api\dotnet\DotnetBackend.scala

  
/*
 * Licensed to the .NET Foundation under one or more agreements.
 * The .NET Foundation licenses this file to you under the MIT license.
 * See the LICENSE file in the project root for more information.
 */

package org.apache.spark.api.dotnet

import java.io.DataOutputStream
import java.net.{InetSocketAddress, Socket}
import java.util.concurrent.{BlockingQueue, LinkedBlockingQueue, TimeUnit}

import io.netty.bootstrap.ServerBootstrap
import io.netty.channel.nio.NioEventLoopGroup
import io.netty.channel.socket.SocketChannel
import io.netty.channel.socket.nio.NioServerSocketChannel
import io.netty.channel.{ChannelFuture, ChannelInitializer, EventLoopGroup}
import io.netty.handler.codec.LengthFieldBasedFrameDecoder
import io.netty.handler.codec.bytes.{ByteArrayDecoder, ByteArrayEncoder}
import org.apache.spark.internal.Logging

/**
 * Netty server that invokes JVM calls based upon receiving messages from .NET.
 * The implementation mirrors the RBackend.
 *
 */
class DotnetBackend extends Logging {
  self => // for accessing the this reference in inner class(ChannelInitializer)
  private[this] var channelFuture: ChannelFuture = _
  private[this] var bootstrap: ServerBootstrap = _
  private[this] var bossGroup: EventLoopGroup = _

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