Module io.netty5.handler

Package io.netty5.handler.flush

Class FlushConsolidationHandler

java.lang.Object

io.netty5.handler.flush.FlushConsolidationHandler

All Implemented Interfaces:

io.netty5.channel.ChannelHandler

public class FlushConsolidationHandler
extends Object
implements io.netty5.channel.ChannelHandler

ChannelHandler which consolidates Channel.flush() / ChannelHandlerContext.flush() operations (which also includes Channel.writeAndFlush(Object) and ChannelOutboundInvoker.writeAndFlush(Object).

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, ChannelHandler.flush(ChannelHandlerContext) will not be passed on to the next ChannelHandler 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:

• if false, flushes are passed on to the next handler directly;
• if 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.

If 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.

Field Summary

Fields

Modifier and Type	Field	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 Summary

Constructors

Constructor	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.

Method Summary

Modifier and Type	Method	Description
void	channelExceptionCaught(io.netty5.channel.ChannelHandlerContext ctx, Throwable cause)
void	channelRead(io.netty5.channel.ChannelHandlerContext ctx, Object msg)
void	channelReadComplete(io.netty5.channel.ChannelHandlerContext ctx)
void	channelWritabilityChanged(io.netty5.channel.ChannelHandlerContext ctx)
io.netty5.util.concurrent.Future<Void>	close(io.netty5.channel.ChannelHandlerContext ctx)
io.netty5.util.concurrent.Future<Void>	disconnect(io.netty5.channel.ChannelHandlerContext ctx)
void	flush(io.netty5.channel.ChannelHandlerContext ctx)
void	handlerAdded(io.netty5.channel.ChannelHandlerContext ctx)
void	handlerRemoved(io.netty5.channel.ChannelHandlerContext ctx)

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty5.channel.ChannelHandler

bind, channelActive, channelInactive, channelInboundEvent, channelRegistered, channelShutdown, channelUnregistered, connect, deregister, isSharable, pendingOutboundBytes, read, register, sendOutboundEvent, shutdown, write

Field Detail

DEFAULT_EXPLICIT_FLUSH_AFTER_FLUSHES

public static final 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).

See Also:

Constant Field Values

Constructor Detail

FlushConsolidationHandler

public FlushConsolidationHandler()

Create new instance which explicit flush after 256 pending flush operations at the latest.

FlushConsolidationHandler

public FlushConsolidationHandler(int explicitFlushAfterFlushes)

Create new instance which doesn't consolidate flushes when no read is in progress.

Parameters:

explicitFlushAfterFlushes - the number of flushes after which an explicit flush will be done.

FlushConsolidationHandler

public FlushConsolidationHandler(int explicitFlushAfterFlushes,
                                 boolean consolidateWhenNoReadInProgress)

Create new instance.

Parameters:

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.

Method Detail

handlerAdded

public void handlerAdded(io.netty5.channel.ChannelHandlerContext ctx)
                  throws Exception

Specified by:

handlerAdded in interface io.netty5.channel.ChannelHandler

Throws:

Exception

flush

public void flush(io.netty5.channel.ChannelHandlerContext ctx)

Specified by:

flush in interface io.netty5.channel.ChannelHandler

channelReadComplete

public void channelReadComplete(io.netty5.channel.ChannelHandlerContext ctx)
                         throws Exception

Specified by:

channelReadComplete in interface io.netty5.channel.ChannelHandler

Throws:

Exception

channelRead

public void channelRead(io.netty5.channel.ChannelHandlerContext ctx,
                        Object msg)
                 throws Exception

Specified by:

channelRead in interface io.netty5.channel.ChannelHandler

Throws:

Exception

channelExceptionCaught

public void channelExceptionCaught(io.netty5.channel.ChannelHandlerContext ctx,
                                   Throwable cause)
                            throws Exception

Specified by:

channelExceptionCaught in interface io.netty5.channel.ChannelHandler

Throws:

Exception

disconnect

public io.netty5.util.concurrent.Future<Void> disconnect(io.netty5.channel.ChannelHandlerContext ctx)

Specified by:

disconnect in interface io.netty5.channel.ChannelHandler

close

public io.netty5.util.concurrent.Future<Void> close(io.netty5.channel.ChannelHandlerContext ctx)

Specified by:

close in interface io.netty5.channel.ChannelHandler

channelWritabilityChanged

public void channelWritabilityChanged(io.netty5.channel.ChannelHandlerContext ctx)
                               throws Exception

Specified by:

channelWritabilityChanged in interface io.netty5.channel.ChannelHandler

Throws:

Exception

handlerRemoved

public void handlerRemoved(io.netty5.channel.ChannelHandlerContext ctx)
                    throws Exception

Specified by:

handlerRemoved in interface io.netty5.channel.ChannelHandler

Throws:

Exception