xml-dev - RE: What is XP?

[Michael Brennan <Michael_Brennan@Allegis.com>]

Well, there was a debate about this on the xml-dist-app list. Since I
followed that debate with interest, I'll pretend that's what we are all
talking about rather than eXtreme Programming. :-)

ebXML has tried to solve a larger set of problems than SOAP. SOAP takes a
minimalist approach. It defines a very simple XML-based messaging protocol.
It explicitly doesn't address issues such as security, reliable delivery of
messages, etc. These latter issues are critical to ecommerce, but the SOAP
philosophy is to build something simple and minimalistic, but also
extensible so solutions to these other issues can be addressed with other
specs and layered on top of SOAP. ebXML, in contrast, tries to tackle all of
these issues up front, as well as support for sending arbitrary binary data.
(ebXML uses MIME/multipart format for the outer envelope, not XML.)

Some (such as Sun) continue to disparage SOAP and point out there are too
many issues it doesn't solve. Sun touts ebXML as a more robust alternative
to SOAP. Those who defend SOAP rightly point out that this misses the whole
point; other capabilities can be layered on top of SOAP. In addition, some
have characterized ebXML as too heavyweight for simple uses. ebXML defenders
point out that you don't have to use everything ebXML offers, and it can be
used for lightweight messaging as well (although I don't think ebXML
provides an RPC mapping like SOAP does).

In the debate on the xml-dist-app list there seemed to be consensus that
convergence is both feasible and desirable. Those affiliated with the ebXML
effort seemed to agree that ebXML could be implemented as a layer on top of
SOAP. Furthermore, the charter of the XP working group (and the sentiments
generally expressed by the participants) is consistent with the SOAP
philosophy: develop a minimalist protocol that is good enough for the simple
cases and serves as a suitable substrate for the more complex cases.
However, since they are still in the requirements phase, we still have quite
a ways to go before we know what XP will look like.

As anyone can probably tell, I'm taking a great interest in this activity.
Partly because it has immediate relevance to the work I am doing with XML;
but it is also  certainly facinating watching how the XML world is evolving,
isn't it?

The other aspect of this I have great interest in is the emergence of
data-binding tools that leverage XSD (or other schema languages). If anyone
encounters (or develops) cool tools for this, please share the info with the
list -- or at least with me. :-)

> -----Original Message-----
> From: Dave Winer [mailto:dave@userland.com]
> Sent: Friday, December 15, 2000 2:17 AM
> To: xml-dev@lists.xml.org
> Subject: What is XP?
> 
> 
> Just curious.. I wonder if XP is at the stage yet where 
> there's a statement
> of how it will differ from SOAP and XML-RPC? I've caught a 
> wiff of a debate
> about how it compares to ebXML, but I'm not so sure I get 
> what ebXML is. I
> know what SOAP and XML-RPC are. Dave
> 
>