public class ChunkedWriteHandler extends Object implements ChannelUpstreamHandler, ChannelDownstreamHandler, LifeCycleAwareChannelHandler
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:
Once inserted, you can write aChannelPipeline
p = ...; p.addLast("streamer", newChunkedWriteHandler
()); p.addLast("handler", new MyHandler());
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(newChunkedFile
(new File("video.mkv"));
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()
.ChannelHandler.Sharable
Constructor and Description |
---|
ChunkedWriteHandler() |
Modifier and Type | Method and Description |
---|---|
void |
afterAdd(ChannelHandlerContext ctx) |
void |
afterRemove(ChannelHandlerContext ctx) |
void |
beforeAdd(ChannelHandlerContext ctx) |
void |
beforeRemove(ChannelHandlerContext ctx) |
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.
|
public void resumeTransfer()
public void handleDownstream(ChannelHandlerContext ctx, ChannelEvent e) throws Exception
ChannelDownstreamHandler
handleDownstream
in interface ChannelDownstreamHandler
ctx
- the context object for this handlere
- the downstream event to process or interceptException
public void handleUpstream(ChannelHandlerContext ctx, ChannelEvent e) throws Exception
ChannelUpstreamHandler
handleUpstream
in interface ChannelUpstreamHandler
ctx
- the context object for this handlere
- the upstream event to process or interceptException
public void beforeAdd(ChannelHandlerContext ctx) throws Exception
beforeAdd
in interface LifeCycleAwareChannelHandler
Exception
public void afterAdd(ChannelHandlerContext ctx) throws Exception
afterAdd
in interface LifeCycleAwareChannelHandler
Exception
public void beforeRemove(ChannelHandlerContext ctx) throws Exception
beforeRemove
in interface LifeCycleAwareChannelHandler
Exception
public void afterRemove(ChannelHandlerContext ctx) throws Exception
afterRemove
in interface LifeCycleAwareChannelHandler
Exception
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