io.netty.handler.flow

Class FlowControlHandler

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.ChannelDuplexHandler

io.netty.handler.flow.FlowControlHandler

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler, io.netty.channel.ChannelOutboundHandler

public class FlowControlHandler
extends io.netty.channel.ChannelDuplexHandler

The FlowControlHandler ensures that only one message per read() is sent downstream. Classes such as ByteToMessageDecoder or MessageToByteEncoder are free to emit as many events as they like for any given input. A channel's auto reading configuration doesn't usually apply in these scenarios. This is causing problems in downstream ChannelHandlers that would like to hold subsequent events while they're processing one event. It's a common problem with the HttpObjectDecoder that will very often fire a HttpRequest that is immediately followed by a LastHttpContent event.

{@code
 ChannelPipeline pipeline = ...;

 pipeline.addLast(new HttpServerCodec());
 pipeline.addLast(new FlowControlHandler());

 pipeline.addLast(new MyExampleHandler());

 class MyExampleHandler extends ChannelInboundHandlerAdapter {

See Also:

ChannelConfig.setAutoRead(boolean)

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

io.netty.channel.ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor and Description
FlowControlHandler()
FlowControlHandler(boolean releaseMessages)

Method Summary

Modifier and Type	Method and Description
void	channelInactive(io.netty.channel.ChannelHandlerContext ctx)
void	channelRead(io.netty.channel.ChannelHandlerContext ctx, Object msg)
void	channelReadComplete(io.netty.channel.ChannelHandlerContext ctx)
void	handlerAdded(io.netty.channel.ChannelHandlerContext ctx)
void	read(io.netty.channel.ChannelHandlerContext ctx)

Methods inherited from class io.netty.channel.ChannelDuplexHandler

bind, close, connect, deregister, disconnect, flush, write

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty.channel.ChannelHandler

exceptionCaught, handlerRemoved

Constructor Detail

FlowControlHandler

public FlowControlHandler()

FlowControlHandler

public FlowControlHandler(boolean releaseMessages)

Method Detail

handlerAdded

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

Specified by:

handlerAdded in interface io.netty.channel.ChannelHandler

Overrides:

handlerAdded in class io.netty.channel.ChannelHandlerAdapter

Throws:

Exception

channelInactive

public void channelInactive(io.netty.channel.ChannelHandlerContext ctx)
                     throws Exception

Specified by:

channelInactive in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelInactive in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

read

public void read(io.netty.channel.ChannelHandlerContext ctx)
          throws Exception

Specified by:

read in interface io.netty.channel.ChannelOutboundHandler

Overrides:

read in class io.netty.channel.ChannelDuplexHandler

Throws:

Exception

channelRead

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

Specified by:

channelRead in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelRead in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

channelReadComplete

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

Specified by:

channelReadComplete in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelReadComplete in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception