Re: Using unbounded sequences

From: Dennis Sosnoski <>
Date: Thu, 25 Mar 2004 10:09:34 -0800

While my understanding of rpc/lit matches Marc's, my earlier comments on
doc/lit vs rpc/lit still hold. I can see very little in the way of
advantages for rpc/lit and many disadvantages (including
interoperability, as Anne pointed out). I'm also not sure about Marc's
claim that a schema definition can be synthesized for rpc/lit based on
the WSDL. This goes back to my earlier question about the message
components representing parameters - are the names of these components
actually fixed by the WSDL, or only the types? My understanding is that
only the types are fixed, which would mean that a schema could not be
constructed from the WSDL.

As I see it, rpc/lit is a way of holding on to the original method call
model of SOAP. I think this model is too limited to be usable for
general processing. Why support something that's admittedly a subset of
the other approach, also supported? I know a number of people who train
developers on web services (including myself) and have yet to meet one
who advocates (or even discusses in any depth) the use of rpc/lit,
instead moving students directly from rpc/enc to doc/lit.

As for WS-I BP 1.0a, I do not see any requirement in the document that
implementations support both doc/lit and rpc/lit. Instead, it defines
the restrictions on how each of these alternatives is to operate. There
are other places in the document where support for a particular feature
is required, and that is clearly stated (for instance: "R4001 A RECEIVER
MUST accept messages that include the Unicode Byte Order Mark (BOM).").
If the BP 1.0a writers did indeed intent to require support for both
doc/lit and rpc/lit they did an amazingly poor job of stating that in
the document, which seems very inconsistent with the rest of their
careful work.

  - Dennis

Dennis M. Sosnoski
Enterprise Java, XML, and Web Services
Training and Consulting
Redmond, WA  425.885.7197
Anderson Jonathan wrote:
>Wow, if that's true then I've read a lot of misleading literature about WSDL
>rpc/literal.  I thought what Anne thought - it must be a very common
>misunderstanding to associate WSDL binding style="rpc" and SOAP RPC.
>	-Jon
>Marc Hadley wrote:
>>The association isn't between rpc and the encoding, its between rpc and
>>the data model. I don't think the SOAP 1.1 authors were really thinking
>>in terms of WSDL, that came later. Only rpc/encoded is really suitable
>>for use with the SOAP rpc convention. rpc/literal is just a WSDL
>>convention that cuts down the amount of schema definitions you need.
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