public class FlushConsolidationHandler
extends io.netty.channel.ChannelDuplexHandler
ChannelDuplexHandler
which consolidates Channel.flush()
/ ChannelHandlerContext.flush()
operations (which also includes
ChannelOutboundInvoker.writeAndFlush(Object)
/ ChannelOutboundInvoker.writeAndFlush(Object, ChannelPromise)
and
ChannelOutboundInvoker.writeAndFlush(Object)
/
ChannelOutboundInvoker.writeAndFlush(Object, ChannelPromise)
).
Flush operations are generally speaking expensive as these may trigger a syscall on the transport level. Thus it is in most cases (where write latency can be traded with throughput) a good idea to try to minimize flush operations as much as possible.
If a read loop is currently ongoing, flush(ChannelHandlerContext)
will not be passed on to the next
ChannelOutboundHandler
in the ChannelPipeline
, as it will pick up any pending flushes when
channelReadComplete(ChannelHandlerContext)
is triggered.
If no read loop is ongoing, the behavior depends on the consolidateWhenNoReadInProgress
constructor argument:
false
, flushes are passed on to the next handler directly;true
, the invocation of the next handler is submitted as a separate task on the event loop. Under
high throughput, this gives the opportunity to process other flushes before the task gets executed, thus
batching multiple flushes into one.explicitFlushAfterFlushes
is reached the flush will be forwarded as well (whether while in a read loop, or
while batching outside of a read loop).
If the Channel
becomes non-writable it will also try to execute any pending flush operations.
The FlushConsolidationHandler
should be put as first ChannelHandler
in the
ChannelPipeline
to have the best effect.
Modifier and Type | Field and Description |
---|---|
static int |
DEFAULT_EXPLICIT_FLUSH_AFTER_FLUSHES
The default number of flushes after which a flush will be forwarded to downstream handlers (whether while in a
read loop, or while batching outside of a read loop).
|
Constructor and Description |
---|
FlushConsolidationHandler()
Create new instance which explicit flush after 256 pending flush
operations at the latest.
|
FlushConsolidationHandler(int explicitFlushAfterFlushes)
Create new instance which doesn't consolidate flushes when no read is in progress.
|
FlushConsolidationHandler(int explicitFlushAfterFlushes,
boolean consolidateWhenNoReadInProgress)
Create new instance.
|
Modifier and Type | Method and Description |
---|---|
void |
channelRead(io.netty.channel.ChannelHandlerContext ctx,
Object msg) |
void |
channelReadComplete(io.netty.channel.ChannelHandlerContext ctx) |
void |
channelWritabilityChanged(io.netty.channel.ChannelHandlerContext ctx) |
void |
close(io.netty.channel.ChannelHandlerContext ctx,
io.netty.channel.ChannelPromise promise) |
void |
disconnect(io.netty.channel.ChannelHandlerContext ctx,
io.netty.channel.ChannelPromise promise) |
void |
exceptionCaught(io.netty.channel.ChannelHandlerContext ctx,
Throwable cause) |
void |
flush(io.netty.channel.ChannelHandlerContext ctx) |
void |
handlerAdded(io.netty.channel.ChannelHandlerContext ctx) |
void |
handlerRemoved(io.netty.channel.ChannelHandlerContext ctx) |
bind, connect, deregister, read, write
public static final int DEFAULT_EXPLICIT_FLUSH_AFTER_FLUSHES
public FlushConsolidationHandler()
public FlushConsolidationHandler(int explicitFlushAfterFlushes)
explicitFlushAfterFlushes
- the number of flushes after which an explicit flush will be done.public FlushConsolidationHandler(int explicitFlushAfterFlushes, boolean consolidateWhenNoReadInProgress)
explicitFlushAfterFlushes
- the number of flushes after which an explicit flush will be done.consolidateWhenNoReadInProgress
- whether to consolidate flushes even when no read loop is currently
ongoing.public void handlerAdded(io.netty.channel.ChannelHandlerContext ctx) throws Exception
handlerAdded
in interface io.netty.channel.ChannelHandler
handlerAdded
in class io.netty.channel.ChannelHandlerAdapter
Exception
public void flush(io.netty.channel.ChannelHandlerContext ctx) throws Exception
flush
in interface io.netty.channel.ChannelOutboundHandler
flush
in class io.netty.channel.ChannelDuplexHandler
Exception
public void channelReadComplete(io.netty.channel.ChannelHandlerContext ctx) throws Exception
channelReadComplete
in interface io.netty.channel.ChannelInboundHandler
channelReadComplete
in class io.netty.channel.ChannelInboundHandlerAdapter
Exception
public void channelRead(io.netty.channel.ChannelHandlerContext ctx, Object msg) throws Exception
channelRead
in interface io.netty.channel.ChannelInboundHandler
channelRead
in class io.netty.channel.ChannelInboundHandlerAdapter
Exception
public void exceptionCaught(io.netty.channel.ChannelHandlerContext ctx, Throwable cause) throws Exception
exceptionCaught
in interface io.netty.channel.ChannelHandler
exceptionCaught
in interface io.netty.channel.ChannelInboundHandler
exceptionCaught
in class io.netty.channel.ChannelInboundHandlerAdapter
Exception
public void disconnect(io.netty.channel.ChannelHandlerContext ctx, io.netty.channel.ChannelPromise promise) throws Exception
disconnect
in interface io.netty.channel.ChannelOutboundHandler
disconnect
in class io.netty.channel.ChannelDuplexHandler
Exception
public void close(io.netty.channel.ChannelHandlerContext ctx, io.netty.channel.ChannelPromise promise) throws Exception
close
in interface io.netty.channel.ChannelOutboundHandler
close
in class io.netty.channel.ChannelDuplexHandler
Exception
public void channelWritabilityChanged(io.netty.channel.ChannelHandlerContext ctx) throws Exception
channelWritabilityChanged
in interface io.netty.channel.ChannelInboundHandler
channelWritabilityChanged
in class io.netty.channel.ChannelInboundHandlerAdapter
Exception
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