Package io.netty.handler.codec.xml
Class XmlFrameDecoder
java.lang.Object
io.netty.channel.ChannelHandlerAdapter
io.netty.channel.ChannelInboundHandlerAdapter
io.netty.handler.codec.ByteToMessageDecoder
io.netty.handler.codec.xml.XmlFrameDecoder
- All Implemented Interfaces:
ChannelHandler
,ChannelInboundHandler
A frame decoder for single separate XML based message streams.
A couple examples will better help illustrate
what this decoder actually does.
Given an input array of bytes split over 3 frames like this:
+-----+-----+-----------+ | <an | Xml | Element/> | +-----+-----+-----------+this decoder would output a single frame:
+-----------------+ | <anXmlElement/> | +-----------------+Given an input array of bytes split over 5 frames like this:
+-----+-----+-----------+-----+----------------------------------+ | <an | Xml | Element/> | <ro | ot><child>content</child></root> | +-----+-----+-----------+-----+----------------------------------+this decoder would output two frames:
+-----------------+-------------------------------------+ | <anXmlElement/> | <root><child>content</child></root> | +-----------------+-------------------------------------+The byte stream is expected to be in UTF-8 character encoding or ASCII. The current implementation uses direct
byte
to char
cast and then compares that char
to a few low range
ASCII characters like '<'
, '>'
or '/'
. UTF-8 is not using low range [0..0x7F]
byte values for multibyte codepoint representations therefore fully supported by this implementation.
Please note that this decoder is not suitable for
xml streaming protocols such as
XMPP,
where an initial xml element opens the stream and only
gets closed at the end of the session, although this class
could probably allow for such type of message flow with
minor modifications.-
Nested Class Summary
Nested classes/interfaces inherited from class io.netty.handler.codec.ByteToMessageDecoder
ByteToMessageDecoder.Cumulator
Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler
ChannelHandler.Sharable
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Field Summary
FieldsFields inherited from class io.netty.handler.codec.ByteToMessageDecoder
COMPOSITE_CUMULATOR, MERGE_CUMULATOR
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected void
decode
(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) Decode the from oneByteBuf
to an other.private static ByteBuf
extractFrame
(ByteBuf buffer, int index, int length) private void
fail
(long frameLength) private static void
private static boolean
isCDATABlockStart
(ByteBuf in, int i) private static boolean
isCommentBlockStart
(ByteBuf in, int i) private static boolean
isValidStartCharForXmlElement
(byte b) Asks whether the given byte is a valid start char for an xml element name.Methods inherited from class io.netty.handler.codec.ByteToMessageDecoder
actualReadableBytes, callDecode, channelInactive, channelRead, channelReadComplete, decodeLast, discardSomeReadBytes, handlerRemoved, handlerRemoved0, internalBuffer, isSingleDecode, setCumulator, setDiscardAfterReads, setSingleDecode, userEventTriggered
Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter
channelActive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught
Methods inherited from class io.netty.channel.ChannelHandlerAdapter
ensureNotSharable, handlerAdded, 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
handlerAdded
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Field Details
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maxFrameLength
private final int maxFrameLength
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Constructor Details
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XmlFrameDecoder
public XmlFrameDecoder(int maxFrameLength)
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Method Details
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decode
Description copied from class:ByteToMessageDecoder
Decode the from oneByteBuf
to an other. This method will be called till either the inputByteBuf
has nothing to read when return from this method or till nothing was read from the inputByteBuf
.- Specified by:
decode
in classByteToMessageDecoder
- Parameters:
ctx
- theChannelHandlerContext
which thisByteToMessageDecoder
belongs toin
- theByteBuf
from which to read dataout
- theList
to which decoded messages should be added- Throws:
Exception
- is thrown if an error occurs
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fail
private void fail(long frameLength) -
fail
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extractFrame
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isValidStartCharForXmlElement
private static boolean isValidStartCharForXmlElement(byte b) Asks whether the given byte is a valid start char for an xml element name. Please refer to the NameStartChar formal definition in the W3C XML spec for further info.- Parameters:
b
- the input char- Returns:
- true if the char is a valid start char
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isCommentBlockStart
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isCDATABlockStart
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