On Mon, 2006-04-17 at 20:12 +0100, Dan Creswell wrote:
>
> Isn't the argument supposed to be that even those systems that don't
> support it can still be relatively easily integrated? Or are we
> actually stating (perhaps as the politics comment below suggests) that
> we expect all suppliers of all products to provide support out of the box?
That's exactly what I'm saying .. :). The following may be far fetched
today for WS-*, but let me give you two analogies:
(1) English: If you do business in China, you do it in Chinese (or
Mandarin or whatever). If its in Japan, its Japanese. If you want to do
biz between China and Japan, then you can either:
- buy a J2C connector in China to convert to Japanese (or vice versa in
Japan)
- or both convert to some common format
The latter approach is what EDI was. What CORBA/IIOP was. What RMI/IIOP
was. And XML/WS-* is. The only advantage XML (and WS-*) has over those
is that its not by design advantaging one platform (e.g., Endian-ness of
IIOP) and therefore everyone's willing to support it by converting to
it. That is, the Chinese and the Japanese will do business with each
other by using English as the integration language: they will each
convert to English.
(2) IP: No, not the intellectual property variety but rather the
Inter-net Protocol variety :-). Why was IP created? Because back then
there were all kinds of other network protocols that were used in
islands of networks. Hence the need for the "inter-"net protocol to
bridge all those disparate networks. IP is like the English or the WS-*
of the integration world. Over time, everyone started offering IP
support .. and of course now we no longer have any other network for the
most part (except in high end scenarios) and IP finds its way directly
into my computer and probably yours.
The legacy view of WS-* is that the world is a big J2EE island or a
big .Net island or a big CORBA island or whatever and you drop down to
this crappy, heavy, slow WS-* thing when you're in one of those rare
situations where you want to bridge those islands together. Doesn't that
look like the IP picture back in the 70s and the 80s? Over time those
"rare situations" (talking to a partner, outsourcing some service,
talking to a customer, dealing with an M&A etc.) will become more and
more commonplace.
My expectation is that the rationale for doing anything but
XML/WS-*/HTTP for communication and integration is going to erode fast
and we'll all be doing that very soon.
Oh yes, I've drunk the kool-aid all the way .. ;-).
-----
Since you asked in an earlier thread, here's some of my WS-* background:
- I'm to be blamed for a good part of the monstrocity called WSDL (1.0
and 1.1) ;-) .. myself and a colleague in IBM took NASSSL (Network
Application Service Specification Language; something we created) and
merged it with SDL from Microsoft and created WSDL. In the W3C I've been
an editor of the WSDL 2.0 specs since that effort started.
- I did the first public SOAP impl (Apache SOAP) which confused the
world by giving a way to take a Java class and make it into a service.
Doh. That was dumb. But I too thought then that WS-* == RPC over XML.
Not any more but that was then.
- I helped create WSFL and then was a key part of creating BPEL 1.0 by
merging WSFL and XLANG (from MSFT). That was actually quite fun ;-).
- Contributed to a bunch of other WS-* specs, including WS-Addressing,
WS-Policy, WS-Eventing, WS-RF (not one I'm proud of any more I'm
afraid).
- I quit IBM Research last year to start WSO2 which is a company focused
on building Web services centric middleware platforms.
I also started into Web services with a view that it was bridge you need
to cross every once-in-a-while and hence the right way to do it was by
facading your existing middleware and programming model with some XML
Schema and WSDL.
Over time I changed my mind and am now convinced that that's all
wrong .. XML is not a serialization format for an object type system and
you need to deal with it as XML. WS-* is not about invoking functions
remotely but rather about delivering XML messages from point A to point
B and letting it do whatever it wants with it and applying policies to
those messages at various points. That's the design point of WSDL 2.0,
WS-Policy, SOAP 1.2 and of Apache Axis2.
Sanjiva.
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