Netty5/Handler 5.0.0.Alpha5 · io.netty5.handler.flush.FlushConsolidationHandler

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

Modifier and Type	Field and Description
private final boolean	consolidateWhenNoReadInProgress
private ChannelHandlerContext	ctx
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).
private final int	explicitFlushAfterFlushes
private int	flushPendingCount
private final Runnable	flushTask
private Future<?>	nextScheduledFlush
private boolean	readInProgress

Constructor Summary

Access	Constructor and Description
public	FlushConsolidationHandler() Create new instance which explicit flush after 256 pending flush operations at the latest.
public	FlushConsolidationHandler(int the number of flushes after which an explicit flush will be done. explicitFlushAfterFlushes) Create new instance which doesn't consolidate flushes when no read is in progress.
public	FlushConsolidationHandler(int the number of flushes after which an explicit flush will be done. explicitFlushAfterFlushes, boolean whether to consolidate flushes even when no read loop is currently ongoing. consolidateWhenNoReadInProgress) Create new instance.

Method Summary

Modifier and Type	Method and Description
private void	cancelScheduledFlush()
public void	channelExceptionCaught(ChannelHandlerContext ctx, Throwable cause) Overrides default io.netty5.channel.ChannelHandler.channelExceptionCaught. Gets called if a `Throwable` was thrown when handling inbound events.
public void	channelRead(ChannelHandlerContext ctx, Object msg) Overrides default io.netty5.channel.ChannelHandler.channelRead. Invoked when the current `Channel` has read a message from the peer.
public void	channelReadComplete(ChannelHandlerContext ctx) Overrides default io.netty5.channel.ChannelHandler.channelReadComplete. Invoked when the last message read by the current read operation has been consumed by `channelRead(ChannelHandlerContext, Object)`.
public void	channelWritabilityChanged(ChannelHandlerContext ctx) Overrides default io.netty5.channel.ChannelHandler.channelWritabilityChanged. Gets called once the writable state of a `Channel` changed.
public Future<Void>	close(ChannelHandlerContext the `ChannelHandlerContext` for which the close operation is made ctx) Overrides default io.netty5.channel.ChannelHandler.close. Called once a close operation is made.
public Future<Void>	disconnect(ChannelHandlerContext the `ChannelHandlerContext` for which the disconnect operation is made ctx) Overrides default io.netty5.channel.ChannelHandler.disconnect. Called once a disconnect operation is made.
public void	flush(ChannelHandlerContext the `ChannelHandlerContext` for which the flush operation is made ctx) Overrides default io.netty5.channel.ChannelHandler.flush. Called once a flush operation is made.
private void	flushIfNeeded(ChannelHandlerContext ctx)
private void	flushNow(ChannelHandlerContext ctx)
public void	handlerAdded(ChannelHandlerContext ctx) Overrides default io.netty5.channel.ChannelHandler.handlerAdded. Gets called after the `ChannelHandler` was added to the actual context and it's ready to handle events.
public void	handlerRemoved(ChannelHandlerContext ctx) Overrides default io.netty5.channel.ChannelHandler.handlerRemoved. Gets called after the `ChannelHandler` was removed from the actual context and it doesn't handle events anymore.
private void	resetReadAndFlushIfNeeded(ChannelHandlerContext ctx)
private void	scheduleFlush(final ChannelHandlerContext ctx)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

consolidateWhenNoReadInProgress	back to summary
private final boolean consolidateWhenNoReadInProgress

ctx	back to summary
private ChannelHandlerContext ctx

DEFAULT_EXPLICIT_FLUSH_AFTER_FLUSHES	back to summary
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).

explicitFlushAfterFlushes	back to summary
private final int explicitFlushAfterFlushes

flushPendingCount	back to summary
private int flushPendingCount

flushTask	back to summary
private final Runnable flushTask

nextScheduledFlush	back to summary
private Future<?> nextScheduledFlush

readInProgress	back to summary
private boolean readInProgress

Constructor Detail

FlushConsolidationHandler	back to summary
public FlushConsolidationHandler() Create new instance which explicit flush after 256 pending flush operations at the latest.

FlushConsolidationHandler	back to summary
public FlushConsolidationHandler(int explicitFlushAfterFlushes) Create new instance which doesn't consolidate flushes when no read is in progress. Parameters explicitFlushAfterFlushes:int the number of flushes after which an explicit flush will be done.

FlushConsolidationHandler

back to summary

public FlushConsolidationHandler(int explicitFlushAfterFlushes)

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

Parameters

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

FlushConsolidationHandler	back to summary
public FlushConsolidationHandler(int explicitFlushAfterFlushes, boolean consolidateWhenNoReadInProgress) Create new instance. Parameters explicitFlushAfterFlushes:int the number of flushes after which an explicit flush will be done. consolidateWhenNoReadInProgress:boolean whether to consolidate flushes even when no read loop is currently ongoing.

FlushConsolidationHandler

back to summary

public FlushConsolidationHandler(int explicitFlushAfterFlushes, boolean consolidateWhenNoReadInProgress)

Create new instance.

Parameters

explicitFlushAfterFlushes:int: the number of flushes after which an explicit flush will be done.
consolidateWhenNoReadInProgress:boolean: whether to consolidate flushes even when no read loop is currently ongoing.

Method Detail

cancelScheduledFlush	back to summary
private void cancelScheduledFlush()

channelExceptionCaught back to summary

channelExceptionCaught	back to summary
public void channelExceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception Overrides default io.netty5.channel.ChannelHandler.channelExceptionCaught. Doc from io.netty5.channel.ChannelHandler.channelExceptionCaught. Gets called if a `Throwable` was thrown when handling inbound events. Annotations @Override

public void channelExceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception

Overrides default io.netty5.channel.ChannelHandler.channelExceptionCaught.

Doc from io.netty5.channel.ChannelHandler.channelExceptionCaught.

Gets called if a Throwable was thrown when handling inbound events.

Annotations

@Override

channelRead back to summary

channelRead	back to summary
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception Overrides default io.netty5.channel.ChannelHandler.channelRead. Doc from io.netty5.channel.ChannelHandler.channelRead. Invoked when the current `Channel` has read a message from the peer. Annotations @Override

public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception

Overrides default io.netty5.channel.ChannelHandler.channelRead.

Doc from io.netty5.channel.ChannelHandler.channelRead.

Invoked when the current Channel has read a message from the peer.

Annotations

@Override

channelReadComplete back to summary

channelReadComplete	back to summary
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception Overrides default io.netty5.channel.ChannelHandler.channelReadComplete. Doc from io.netty5.channel.ChannelHandler.channelReadComplete. Invoked when the last message read by the current read operation has been consumed by `channelRead(ChannelHandlerContext, Object)`. If `ChannelOption#AUTO_READ` is off, no further attempt to read an inbound data from the current `Channel` will be made until `ChannelOutboundInvoker#read(ReadBufferAllocator)` is called. Annotations @Override

public void channelReadComplete(ChannelHandlerContext ctx) throws Exception

Overrides default io.netty5.channel.ChannelHandler.channelReadComplete.

Doc from io.netty5.channel.ChannelHandler.channelReadComplete.

Invoked when the last message read by the current read operation has been consumed by channelRead(ChannelHandlerContext, Object). If ChannelOption#AUTO_READ is off, no further attempt to read an inbound data from the current Channel will be made until ChannelOutboundInvoker#read(ReadBufferAllocator) is called.

Annotations

@Override

channelWritabilityChanged back to summary

channelWritabilityChanged	back to summary
public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception Overrides default io.netty5.channel.ChannelHandler.channelWritabilityChanged. Doc from io.netty5.channel.ChannelHandler.channelWritabilityChanged. Gets called once the writable state of a `Channel` changed. You can check the state with `Channel#writableBytes()` or `Channel#isWritable()`. Annotations @Override

public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception

Overrides default io.netty5.channel.ChannelHandler.channelWritabilityChanged.

Doc from io.netty5.channel.ChannelHandler.channelWritabilityChanged.

Gets called once the writable state of a Channel changed. You can check the state with Channel#writableBytes() or Channel#isWritable().

Annotations

@Override

close back to summary

close	back to summary
public Future<Void> close(ChannelHandlerContext ctx) Overrides default io.netty5.channel.ChannelHandler.close. Doc from io.netty5.channel.ChannelHandler.close. Called once a close operation is made. Parameters ctx:ChannelHandlerContext the `ChannelHandlerContext` for which the close operation is made Returns:Future<Void> the `Future` which will be notified once the operation completes. Annotations @Override

public Future<Void> close(ChannelHandlerContext ctx)

Overrides default io.netty5.channel.ChannelHandler.close.

Doc from io.netty5.channel.ChannelHandler.close.

Called once a close operation is made.

Parameters

ctx:ChannelHandlerContext: the ChannelHandlerContext for which the close operation is made

Returns:Future<Void>

the Future which will be notified once the operation completes.

Annotations

@Override

disconnect back to summary

disconnect	back to summary
public Future<Void> disconnect(ChannelHandlerContext ctx) Overrides default io.netty5.channel.ChannelHandler.disconnect. Doc from io.netty5.channel.ChannelHandler.disconnect. Called once a disconnect operation is made. Parameters ctx:ChannelHandlerContext the `ChannelHandlerContext` for which the disconnect operation is made Returns:Future<Void> the `Future` which will be notified once the operation completes. Annotations @Override

public Future<Void> disconnect(ChannelHandlerContext ctx)

Overrides default io.netty5.channel.ChannelHandler.disconnect.

Doc from io.netty5.channel.ChannelHandler.disconnect.

Called once a disconnect operation is made.

Parameters

ctx:ChannelHandlerContext: the ChannelHandlerContext for which the disconnect operation is made

Returns:Future<Void>

the Future which will be notified once the operation completes.

Annotations

@Override

flush back to summary

flush	back to summary
public void flush(ChannelHandlerContext ctx) Overrides default io.netty5.channel.ChannelHandler.flush. Doc from io.netty5.channel.ChannelHandler.flush. Called once a flush operation is made. The flush operation will try to flush out all previous written messages that are pending. Parameters ctx:ChannelHandlerContext the `ChannelHandlerContext` for which the flush operation is made Annotations @Override

public void flush(ChannelHandlerContext ctx)

Overrides default io.netty5.channel.ChannelHandler.flush.

Doc from io.netty5.channel.ChannelHandler.flush.

Called once a flush operation is made. The flush operation will try to flush out all previous written messages that are pending.

Parameters

ctx:ChannelHandlerContext: the ChannelHandlerContext for which the flush operation is made

Annotations

@Override

flushIfNeeded	back to summary
private void flushIfNeeded(ChannelHandlerContext ctx)

flushNow	back to summary
private void flushNow(ChannelHandlerContext ctx)

handlerAdded back to summary

handlerAdded	back to summary
public void handlerAdded(ChannelHandlerContext ctx) throws Exception Overrides default io.netty5.channel.ChannelHandler.handlerAdded. Doc from io.netty5.channel.ChannelHandler.handlerAdded. Gets called after the `ChannelHandler` was added to the actual context and it's ready to handle events. Annotations @Override

public void handlerAdded(ChannelHandlerContext ctx) throws Exception

Overrides default io.netty5.channel.ChannelHandler.handlerAdded.

Doc from io.netty5.channel.ChannelHandler.handlerAdded.

Gets called after the ChannelHandler was added to the actual context and it's ready to handle events.

Annotations

@Override

handlerRemoved back to summary

handlerRemoved	back to summary
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception Overrides default io.netty5.channel.ChannelHandler.handlerRemoved. Doc from io.netty5.channel.ChannelHandler.handlerRemoved. Gets called after the `ChannelHandler` was removed from the actual context and it doesn't handle events anymore. Annotations @Override

public void handlerRemoved(ChannelHandlerContext ctx) throws Exception

Overrides default io.netty5.channel.ChannelHandler.handlerRemoved.

Doc from io.netty5.channel.ChannelHandler.handlerRemoved.

Gets called after the ChannelHandler was removed from the actual context and it doesn't handle events anymore.

Annotations

@Override

resetReadAndFlushIfNeeded	back to summary
private void resetReadAndFlushIfNeeded(ChannelHandlerContext ctx)

scheduleFlush	back to summary
private void scheduleFlush(final ChannelHandlerContext ctx)

public Class FlushConsolidationHandler

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail