RE: [JDEV] XML protocol question

[Sean McCullough <banksean@yahoo.com>]

Ooooh sounds like I'll wait for that CVS update!  I 
was just getting a little anxious ;-) I'm actually
trying to solve a very similar problem at work so this was kind of an
experiment for me as well.  I'm looking 
forward to using your additions!

-Sean McCullough


--- Patrick McCuller <patrick@kia.net> wrote:
> 
> 	I am working with JabberBeans and intend to check
> in the first fully
> functional version within a day or so.  I use an XML
> parser in Java to do
> the trick, naturally, and here's what worked for me:
> 
> 	I fully read the packet off the line, build a
> String, and pass it over to
> an XML-aware ProtocolConsumer, which understand the
> Jabber protocol and
> builds JabberBean Packets. From here it gets passed
> to an XML-parser aware
> class which currently relies on IBM's XML4J, but
> could be easily switched to
> something else if need be. This XMLParser class does
> a simple check to see
> whether it is parsable by an Non-Validating (for the
> time being) parser
> (using DOM, not SAX.) If it is not, it attempts to
> make it so by
> ap-or-prepending any required information. So far, I
> have found that simply
> prepending "<? xml version=...?>" type identifiers
> is all it needs to create
> a Document object. JabberBeans passes this back to
> the ProtocolConsumer
> which builds a Packet
> (MessagePacket,RosterPacket,StatusPacket, etc.) from
> the Document.
> 
> 	Thus, this:
> 
> > <message>
> >         <to>jeremie</to>
> >         <say>test</say>
> > </message>
> 
> 	becomes this:
> 
> > <?xml version="1.0"?>
> > <message>
> >         <to>jeremie</to>
> >         <say>test</say>
> > </message>
> 
> 
> 	Does this help at all? The JabberBeans code will go
> in very soon and I can
> send it to you ahead of time if you are interested.
> 
> 
> Patrick McCuller
> 
> 
> 
> 
> > -----Original Message-----
> > From: owner-jdev@jabber.org
> [mailto:owner-jdev@jabber.org]On Behalf Of
> > Sean McCullough
> > Sent: Monday, July 26, 1999 6:56 PM
> > To: jdev@jabber.org
> > Subject: [JDEV] XML protocol question
> >
> >
> > I've been trying to implement a Jabber protocol
> stack in java using the
> > org.xml.sax parser package. (this is not part of
> the JabberBeans
> > project btw)
> >
> > Is there any reason not to wrap top-level elements
> in the Jabber
> > client-server protocol in full xml document tags
> (aside from the size
> > increase)?  I'm running into some design problems
> where I can't take
> > advantage of SAX/DOM the way I want to.  I'm
> trying to read in a series
> > of packets, blocking the requesting thread when
> necessary.  Currently
> > I'm using the SAX DocuemntHandler callback methods
> to figure out when a
> > packet is done reading/parsing so I can wake up
> the reader thread if
> > it's blocking.  This is getting tricky because I
> can't decide if the
> > PacketReader should interpret every element (in
> which case it must know
> > more about Packet subclasses than it should
> (ick)), or if Packet
> > classes should parse their own content (meaning
> Packet must implement
> > DocumentHandler (ick)).  I'd rather use the DOM
> with Sun's JavaBean
> > support, but it's not going to finish parsing
> anything in Jabber
> > session until it reaches the outer </jabber>
> element which (I believe)
> > currently means your session is over :-/
> >
> > so the example at
> >
> http://www.jabber.org/download/latest/doc/protocol/client2server.txt
> >
> > would look like:
> >
> > <?xml version="1.0"?>
> > <jabber version="name/os version/version"
> protocol="19990324">
> >
> > <login>
> >         <user>jeremie</user>
> >         <pass>Ph0niks</pass>
> >         <nick>jabalot</nick>
> > </login>
> >
> > </jabber>
> >
> > <jabber version="name/os version/version"
> protocol="19990324">
> >
> > <message>
> >         <to>jeremie</to>
> >         <say>test</say>
> > </message>
> > </jabber>
> >
> > <jabber version="name/os version/version"
> protocol="19990324">
> >
> > <message>
> >         <to>someone</to>
> >         <to name='Jenny(work)'>jenny</to>
> >         <to>jeremie</to>
> >         <to
> name='HAhah!'>safdsgh@asdfg.asdfasdf</to>
> >         <thread>sdfa</thread>
> >         <priority>1</priority>
> >         <subject>Did you see that?</subject>
> >         <say>asdgf asdfkjasgoijqwert
> asdgaldgjkas</say>
> > </message>
> >
> > </jabber>
> >
> > ...
> >
> >
> > Am I going about this the wrong way?  I know it
> looks like I'm asking
> > for a lot of unnecessary overhead but I can't
> think of a good way to
> > use the available XML tools without it.
> >
> > I suppose a workaround would be to read past the
> opening jabber element
> > before handing the InputStream  over to the DOM,
> but that would
> > probably throw exceptions for the lack of <? xml
> ?> tag and the
> > unexpected ending </jabber>
> >
> > Has anyone else tried to use DOM or SAX to
> implement an XML protocol?
> > I haven't looked at IBM's Java XML parser yet so
> it might better suit
> > what I'm trying to do than Sun's parser.
> >
> > -Sean McCullough
> >
> _________________________________________________________
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> >
> >
> 
> 

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