io.netty.handler.stream

Class ChunkedWriteHandler

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.ChannelDuplexHandler

io.netty.handler.stream.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

Constructor Summary

Constructors

Constructor and Description
ChunkedWriteHandler()
ChunkedWriteHandler(int maxPendingWrites) Deprecated. use ChunkedWriteHandler()

Method Summary

Modifier and Type	Method and 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 class java.lang.Object

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

Methods inherited from interface io.netty.channel.ChannelHandler

exceptionCaught, handlerRemoved

Constructor Detail

ChunkedWriteHandler

public ChunkedWriteHandler()

ChunkedWriteHandler

@Deprecated
public ChunkedWriteHandler(int maxPendingWrites)

Deprecated. use 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