Class Http2MultiplexHandler
- java.lang.Object
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- io.netty.channel.ChannelHandlerAdapter
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- io.netty.channel.ChannelInboundHandlerAdapter
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- io.netty.channel.ChannelDuplexHandler
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- io.netty.handler.codec.http2.Http2ChannelDuplexHandler
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- io.netty.handler.codec.http2.Http2MultiplexHandler
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- All Implemented Interfaces:
ChannelHandler
,ChannelInboundHandler
,ChannelOutboundHandler
public final class Http2MultiplexHandler extends Http2ChannelDuplexHandler
An HTTP/2 handler that creates child channels for each stream. This handler must be used in combination withHttp2FrameCodec
.When a new stream is created, a new
Http2StreamChannel
is created for it. Applications send and receiveHttp2StreamFrame
s on the created channel.ByteBuf
s cannot be processed by the channel; all writes that reach the head of the pipeline must be an instance ofHttp2StreamFrame
. Writes that reach the head of the pipeline are processed directly by this handler and cannot be intercepted.The child channel will be notified of user events that impact the stream, such as
Http2GoAwayFrame
andHttp2ResetFrame
, as soon as they occur. AlthoughHttp2GoAwayFrame
andHttp2ResetFrame
signify that the remote is ignoring further communication, closing of the channel is delayed until any inbound queue is drained withChannel.read()
, which follows the default behavior of channels in Netty. Applications are free to close the channel in response to such events if they don't have use for any queued messages. Any connection level events likeHttp2SettingsFrame
andHttp2GoAwayFrame
will be processed internally and also propagated down the pipeline for other handlers to act on.Outbound streams are supported via the
Http2StreamChannelBootstrap
.ChannelConfig.setMaxMessagesPerRead(int)
andChannelConfig.setAutoRead(boolean)
are supported.Reference Counting
SomeHttp2StreamFrame
s implement theReferenceCounted
interface, as they carry reference counted objects (e.g.ByteBuf
s). The multiplex codec will callReferenceCounted.retain()
before propagating a reference counted object through the pipeline, and thus an application handler needs to release such an object after having consumed it. For more information on reference counting take a look at the reference counted docs.Channel Events
A child channel becomes active as soon as it is registered to anEventLoop
. Therefore, an active channel does not map to an active HTTP/2 stream immediately. Only once aHttp2HeadersFrame
has been successfully sent or received, does the channel map to an active HTTP/2 stream. In case it is not possible to open a new HTTP/2 stream (i.e. due to the maximum number of active streams being exceeded), the child channel receives an exception indicating the cause and is closed immediately thereafter.Writability and Flow Control
A child channel observes outbound/remote flow control via the channel's writability. A channel only becomes writable when it maps to an active HTTP/2 stream . A child channel does not know about the connection-level flow control window.ChannelHandler
s are free to ignore the channel's writability, in which case the excessive writes will be buffered by the parent channel. It's important to note that onlyHttp2DataFrame
s are subject to HTTP/2 flow control.Closing a
Once you close aHttp2StreamChannel
Http2StreamChannel
aHttp2ResetFrame
will be sent to the remote peer withHttp2Error.CANCEL
if needed. If you want to close the stream with anotherHttp2Error
(due errors / limits) you should propagate aHttp2FrameStreamException
through theChannelPipeline
. Once it reaches the end of theChannelPipeline
it will automatically close theHttp2StreamChannel
and send aHttp2ResetFrame
with the unwrappedHttp2Error
set. Another possibility is to just directly write aHttp2ResetFrame
to theHttp2StreamChannel
l.
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Nested Class Summary
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Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler
ChannelHandler.Sharable
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Constructor Summary
Constructors Constructor Description Http2MultiplexHandler(ChannelHandler inboundStreamHandler)
Creates a new instanceHttp2MultiplexHandler(ChannelHandler inboundStreamHandler, ChannelHandler upgradeStreamHandler)
Creates a new instance
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Method Summary
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Methods inherited from class io.netty.handler.codec.http2.Http2ChannelDuplexHandler
forEachActiveStream, handlerAdded, handlerRemoved, newStream
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Methods inherited from class io.netty.channel.ChannelDuplexHandler
bind, close, connect, deregister, disconnect, flush, read, write
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Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter
channelActive, channelInactive, channelRegistered, channelUnregistered
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Methods inherited from class io.netty.channel.ChannelHandlerAdapter
ensureNotSharable, isSharable
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Constructor Detail
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Http2MultiplexHandler
public Http2MultiplexHandler(ChannelHandler inboundStreamHandler)
Creates a new instance- Parameters:
inboundStreamHandler
- theChannelHandler
that will be added to theChannelPipeline
of theChannel
s created for new inbound streams.
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Http2MultiplexHandler
public Http2MultiplexHandler(ChannelHandler inboundStreamHandler, ChannelHandler upgradeStreamHandler)
Creates a new instance- Parameters:
inboundStreamHandler
- theChannelHandler
that will be added to theChannelPipeline
of theChannel
s created for new inbound streams.upgradeStreamHandler
- theChannelHandler
that will be added to theChannelPipeline
of the upgradedChannel
.
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Method Detail
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handlerAdded0
protected void handlerAdded0(ChannelHandlerContext ctx)
- Overrides:
handlerAdded0
in classHttp2ChannelDuplexHandler
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handlerRemoved0
protected void handlerRemoved0(ChannelHandlerContext ctx)
- Overrides:
handlerRemoved0
in classHttp2ChannelDuplexHandler
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channelRead
public void channelRead(ChannelHandlerContext ctx, java.lang.Object msg) throws java.lang.Exception
Description copied from class:ChannelInboundHandlerAdapter
CallsChannelHandlerContext.fireChannelRead(Object)
to forward to the nextChannelInboundHandler
in theChannelPipeline
. Sub-classes may override this method to change behavior.- Specified by:
channelRead
in interfaceChannelInboundHandler
- Overrides:
channelRead
in classChannelInboundHandlerAdapter
- Throws:
java.lang.Exception
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channelWritabilityChanged
public void channelWritabilityChanged(ChannelHandlerContext ctx) throws java.lang.Exception
Description copied from class:ChannelInboundHandlerAdapter
CallsChannelHandlerContext.fireChannelWritabilityChanged()
to forward to the nextChannelInboundHandler
in theChannelPipeline
. Sub-classes may override this method to change behavior.- Specified by:
channelWritabilityChanged
in interfaceChannelInboundHandler
- Overrides:
channelWritabilityChanged
in classChannelInboundHandlerAdapter
- Throws:
java.lang.Exception
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userEventTriggered
public void userEventTriggered(ChannelHandlerContext ctx, java.lang.Object evt) throws java.lang.Exception
Description copied from class:ChannelInboundHandlerAdapter
CallsChannelHandlerContext.fireUserEventTriggered(Object)
to forward to the nextChannelInboundHandler
in theChannelPipeline
. Sub-classes may override this method to change behavior.- Specified by:
userEventTriggered
in interfaceChannelInboundHandler
- Overrides:
userEventTriggered
in classChannelInboundHandlerAdapter
- Throws:
java.lang.Exception
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exceptionCaught
public void exceptionCaught(ChannelHandlerContext ctx, java.lang.Throwable cause) throws java.lang.Exception
Description copied from class:ChannelInboundHandlerAdapter
CallsChannelHandlerContext.fireExceptionCaught(Throwable)
to forward to the nextChannelHandler
in theChannelPipeline
. Sub-classes may override this method to change behavior.- Specified by:
exceptionCaught
in interfaceChannelHandler
- Specified by:
exceptionCaught
in interfaceChannelInboundHandler
- Overrides:
exceptionCaught
in classChannelInboundHandlerAdapter
- Throws:
java.lang.Exception
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channelReadComplete
public void channelReadComplete(ChannelHandlerContext ctx) throws java.lang.Exception
Notifies any child streams of the read completion.- Specified by:
channelReadComplete
in interfaceChannelInboundHandler
- Overrides:
channelReadComplete
in classChannelInboundHandlerAdapter
- Throws:
java.lang.Exception
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