Package io.netty.handler.stream

Class ChunkedWriteHandler

  • All Implemented Interfaces:
    io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler, io.netty.channel.ChannelOutboundHandler
    public class ChunkedWriteHandler
extends io.netty.channel.ChannelDuplexHandler
    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, 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 interface io.netty.channel.ChannelHandler

        handlerRemoved

    • Constructor Detail

      • ChunkedWriteHandler

        public ChunkedWriteHandler()

    • Method Detail

      • handlerAdded

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

      • resumeTransfer

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

      • write

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

      • flush

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

      • channelInactive

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

      • channelWritabilityChanged

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