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
public class XmlFrameDecoder extends 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.