Package io.netty.handler.codec.xml

Class XmlFrameDecoder

  • All Implemented Interfaces:
    io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler
    public class XmlFrameDecoder
extends io.netty.handler.codec.ByteToMessageDecoder
    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

        io.netty.handler.codec.ByteToMessageDecoder.Cumulator

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

        io.netty.channel.ChannelHandler.Sharable

    • Field Summary

      • Fields inherited from class io.netty.handler.codec.ByteToMessageDecoder

        COMPOSITE_CUMULATOR, MERGE_CUMULATOR

    • Constructor Summary

      Constructors 
      Constructor Description
      XmlFrameDecoder​(int maxFrameLength)  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected void decode​(io.netty.channel.ChannelHandlerContext ctx, io.netty.buffer.ByteBuf in, List<Object> out)  

      • 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 interface io.netty.channel.ChannelHandler

        handlerAdded

    • Constructor Detail

      • XmlFrameDecoder

        public XmlFrameDecoder​(int maxFrameLength)

    • Method Detail

      • decode

        protected void decode​(io.netty.channel.ChannelHandlerContext ctx,
                      io.netty.buffer.ByteBuf in,
                      List<Object> out)
               throws Exception
        Specified by:
        decode in class io.netty.handler.codec.ByteToMessageDecoder
        Throws:
        Exception