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Bill de hÓra wrote:
>
>...
>
> This is a holy grail within distributed computing just as much as
> mantra for the people lumbered with the jobs of buying and selling
> middleware. The point of convergence, or agreement, between web
> services (eg XMLP), p2p (eg JXTA) and agent systems (eg FIPA-AA) is
> that networked applications must be allowed to be transport
> agnostic. Transport Agnostic==The Good is an axiom of many
> architectures.
Transport agnosticism makes a lot of sense. If the firewalls of tomorrow
block TCP/IP then you want to be able to switch to IPX or whatever comes
next.
But HTTP is not a transport protocol (though you can use it that way).
It is an application protocol, with a set of generic semantics.
Eventually you need to figure out what the data, addressing and
invocation model of your web service is. You cannot be "model-agnostic."
You must decide. HTTP already gets you far down this path with its URI
addressing model and 4 main methods for invocation. "Abstracting" over
HTTP by erasing its model is not abstracting at all. It's like
implementing the JVM in Lisp and saying that you are now "programming
model independent" because you've put some byte codes over the Lisp
object model. Well, no, you've obliterated the programming model and
someone is going to be forced to build another one on top. And guess
what: you won't be programming model independent anymore!
Paul Prescod
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