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RE: Namespaces, W3C XML Schema (was Re: ANN: SAX Filters forNamespaceProcessing)

> From: Elliotte Rusty Harold [mailto:elharo@metalab.unc.edu]


> >> On the other hand, over the last three years as I've taught 
> >> developers about DTDs, almost invariably the first question 
> >> is "How do I say that an element contains an int?" and the 
> >> second question is usually ""How do I say that an element 
> >> contains a year since 1969?" or some variant thereof. 
> >
> >In other words, people want data-binding, but they want it 
> to be simple.
> >
> No, this isn't data binding at all. It's validation. It's 
> being presented with a set of quantities and verifying that 
> those quantities meet certain predetermined constraints. 

I misread your post. In the context you describe, you are right. This is
just validation. However, I have seen the use case cited quite often of
developers wanting to leverage a schema for data-binding. In some cases,
they just want to be able to access an attribute value or element content as
a meaningful datatype instead of just a string. I've also seen cases where
developers want to just get access to some PSVI info within their
application so they know the datatype of an attribute value or element
content and can deal with it more intelligently within their application.
This is in addition to those cases where developer want to go further and
generate classes from schemas.

So although I misread your post, I have personally heard from many
developers asking "How can I get this attribute value in my program as a
Date", and similar statements. Microsoft is providing some of this
capability with their XML SDK, and at least some developers using their
tools are leveraging this functionality. Developers in the Java world are
left with waiting for JAXB, or using something like Castor (which is not
particularly user-friendly, although perhaps better docs would help), and
the simple use cases are ignored by tools providers -- except Microsoft.