org.jboss.netty.handler.stream

Class ChunkedWriteHandler

java.lang.Object

org.jboss.netty.handler.stream.ChunkedWriteHandler

All Implemented Interfaces:

ChannelDownstreamHandler, ChannelHandler, ChannelUpstreamHandler, LifeCycleAwareChannelHandler

public class ChunkedWriteHandler
extends java.lang.Object
implements ChannelUpstreamHandler, ChannelDownstreamHandler, LifeCycleAwareChannelHandler

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.nextChunk(), 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 org.jboss.netty.channel.ChannelHandler

ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field and Description
private ChannelHandlerContext	ctx
private MessageEvent	currentEvent
private java.util.concurrent.atomic.AtomicBoolean	flush
private boolean	flushNeeded
private static InternalLogger	logger
private java.util.Queue<MessageEvent>	queue

Constructor Summary

Constructors

Constructor and Description
ChunkedWriteHandler()

Method Summary

Modifier and Type	Method and Description
void	afterAdd(ChannelHandlerContext ctx)
void	afterRemove(ChannelHandlerContext ctx)
void	beforeAdd(ChannelHandlerContext ctx)
void	beforeRemove(ChannelHandlerContext ctx)
(package private) static void	closeInput(ChunkedInput chunks)
private void	discard(ChannelHandlerContext ctx, boolean fireNow)
private void	flush(ChannelHandlerContext ctx, boolean fireNow)
void	handleDownstream(ChannelHandlerContext ctx, ChannelEvent e) Handles the specified downstream event.
void	handleUpstream(ChannelHandlerContext ctx, ChannelEvent e) Handles the specified upstream event.
void	resumeTransfer() Continues to fetch the chunks from the input.

Methods inherited from class java.lang.Object

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

Field Detail

logger

private static final InternalLogger logger

queue

private final java.util.Queue<MessageEvent> queue

ctx

private volatile ChannelHandlerContext ctx

flush

private final java.util.concurrent.atomic.AtomicBoolean flush

currentEvent

private MessageEvent currentEvent

flushNeeded

private volatile boolean flushNeeded

Constructor Detail

ChunkedWriteHandler

public ChunkedWriteHandler()

Method Detail

resumeTransfer

public void resumeTransfer()

Continues to fetch the chunks from the input.

handleDownstream

public void handleDownstream(ChannelHandlerContext ctx,
                             ChannelEvent e)
                      throws java.lang.Exception

Description copied from interface: ChannelDownstreamHandler

Handles the specified downstream event.

Specified by:

handleDownstream in interface ChannelDownstreamHandler

Parameters:

ctx - the context object for this handler

e - the downstream event to process or intercept

Throws:

java.lang.Exception

handleUpstream

public void handleUpstream(ChannelHandlerContext ctx,
                           ChannelEvent e)
                    throws java.lang.Exception

Description copied from interface: ChannelUpstreamHandler

Handles the specified upstream event.

Specified by:

handleUpstream in interface ChannelUpstreamHandler

Parameters:

ctx - the context object for this handler

e - the upstream event to process or intercept

Throws:

java.lang.Exception

discard

private void discard(ChannelHandlerContext ctx,
                     boolean fireNow)

flush

private void flush(ChannelHandlerContext ctx,
                   boolean fireNow)
            throws java.lang.Exception

Throws:

java.lang.Exception

closeInput

static void closeInput(ChunkedInput chunks)

beforeAdd

public void beforeAdd(ChannelHandlerContext ctx)
               throws java.lang.Exception

Specified by:

beforeAdd in interface LifeCycleAwareChannelHandler

Throws:

java.lang.Exception

afterAdd

public void afterAdd(ChannelHandlerContext ctx)
              throws java.lang.Exception

Specified by:

afterAdd in interface LifeCycleAwareChannelHandler

Throws:

java.lang.Exception

beforeRemove

public void beforeRemove(ChannelHandlerContext ctx)
                  throws java.lang.Exception

Specified by:

beforeRemove in interface LifeCycleAwareChannelHandler

Throws:

java.lang.Exception

afterRemove

public void afterRemove(ChannelHandlerContext ctx)
                 throws java.lang.Exception

Specified by:

afterRemove in interface LifeCycleAwareChannelHandler

Throws:

java.lang.Exception