Package com.linkedin.venice.router.streaming

Class NettyChunkedWriteHandler

  • All Implemented Interfaces:
    io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler, io.netty.channel.ChannelOutboundHandler
    Direct Known Subclasses:
    VeniceChunkedWriteHandler
    public class NettyChunkedWriteHandler
extends io.netty.channel.ChannelDuplexHandler
    This class was copied from ChunkedWriteHandler, and the only change we made here is to using ConcurrentLinkedQueue for queue since resumeTransfer() or discard(Throwable) could happen in any sequence with any parallelism because of scatter/gather logic in Venice Router. TODO: sync up with Netty team to see whether we could incorporate this change into Netty code base or not. Original Javadoc starts from here: A ChannelHandler that adds support for writing a large data stream asynchronously neither spending a lot of memory nor getting OutOfMemoryError. Large data streaming such as file transfer requires complicated state management in a ChannelHandler implementation. ChunkedWriteHandler manages such complicated states so that you can send a large data stream without difficulties.

    To use ChunkedWriteHandler in your application, you have to insert a new ChunkedWriteHandler instance: 

     ChannelPipeline p = ...;
 p.addLast("streamer", new ChunkedWriteHandler());
 p.addLast("handler", new MyHandler());
    Once inserted, you can write a ChunkedInput so that the ChunkedWriteHandler can pick it up and fetch the content of the stream chunk by chunk and write the fetched chunk downstream: 
     Channel ch = ...;
 ch.write(new ChunkedFile(new File("video.mkv"));

    Sending a stream which generates a chunk intermittently

    Some ChunkedInput generates a chunk on a certain event or timing. Such ChunkedInput implementation often returns null on ChunkedInput.readChunk(ChannelHandlerContext), resulting in the indefinitely suspended transfer. To resume the transfer when a new chunk is available, you have to call resumeTransfer().

    • Nested Class Summary

      • Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

        io.netty.channel.ChannelHandler.Sharable

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void channelInactive​(io.netty.channel.ChannelHandlerContext ctx)  
      void channelWritabilityChanged​(io.netty.channel.ChannelHandlerContext ctx)  
      void flush​(io.netty.channel.ChannelHandlerContext ctx)  
      void handlerAdded​(io.netty.channel.ChannelHandlerContext ctx)  
      void resumeTransfer()
      Continues to fetch the chunks from the input.
      void write​(io.netty.channel.ChannelHandlerContext ctx, java.lang.Object msg, io.netty.channel.ChannelPromise promise)  

      • Methods inherited from class io.netty.channel.ChannelDuplexHandler

        bind, close, connect, deregister, disconnect, read

      • Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

        channelActive, channelRead, channelReadComplete, channelRegistered, channelUnregistered, exceptionCaught, userEventTriggered

      • Methods inherited from class io.netty.channel.ChannelHandlerAdapter

        ensureNotSharable, handlerRemoved, isSharable

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

      • Methods inherited from interface io.netty.channel.ChannelHandler

        handlerRemoved

    • Constructor Detail

      • NettyChunkedWriteHandler

        public NettyChunkedWriteHandler()

      • NettyChunkedWriteHandler

        @Deprecated
public NettyChunkedWriteHandler​(int maxPendingWrites)
        Deprecated.
        use NettyChunkedWriteHandler()

    • Method Detail

      • handlerAdded

        public void handlerAdded​(io.netty.channel.ChannelHandlerContext ctx)
                  throws java.lang.Exception
        Specified by:
        handlerAdded in interface io.netty.channel.ChannelHandler
        Overrides:
        handlerAdded in class io.netty.channel.ChannelHandlerAdapter
        Throws:
        java.lang.Exception

      • resumeTransfer

        public void resumeTransfer()
        Continues to fetch the chunks from the input.

      • write

        public void write​(io.netty.channel.ChannelHandlerContext ctx,
                  java.lang.Object msg,
                  io.netty.channel.ChannelPromise promise)
           throws java.lang.Exception
        Specified by:
        write in interface io.netty.channel.ChannelOutboundHandler
        Overrides:
        write in class io.netty.channel.ChannelDuplexHandler
        Throws:
        java.lang.Exception

      • flush

        public void flush​(io.netty.channel.ChannelHandlerContext ctx)
           throws java.lang.Exception
        Specified by:
        flush in interface io.netty.channel.ChannelOutboundHandler
        Overrides:
        flush in class io.netty.channel.ChannelDuplexHandler
        Throws:
        java.lang.Exception

      • channelInactive

        public void channelInactive​(io.netty.channel.ChannelHandlerContext ctx)
                     throws java.lang.Exception
        Specified by:
        channelInactive in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        channelInactive in class io.netty.channel.ChannelInboundHandlerAdapter
        Throws:
        java.lang.Exception

      • channelWritabilityChanged

        public void channelWritabilityChanged​(io.netty.channel.ChannelHandlerContext ctx)
                               throws java.lang.Exception
        Specified by:
        channelWritabilityChanged in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        channelWritabilityChanged in class io.netty.channel.ChannelInboundHandlerAdapter
        Throws:
        java.lang.Exception