Re: [xml-dev] When to Validate XML?

[Subrahmanyam Allamaraju <subbu@bea.com>]

> However, wildcards and base types can be defined *in a common schema*.
> Certain apps may choose to extend such a schema by extending or restricting
> types in their own local schema. Existing applications operating of the base
> schema definitions can react passively to unknown derived type information. 
> 
> By this I mean that the existing apps can store extra data items introducted
> by unknown (to it) extended types (trusting the authoring app to do it's own
> local schema validation), or inserted in wildcard spots. If that's too
> 'loose' for the application's taste, then the base schema definitions can be
> finalized.


This is more like passing an Object and let each app coerce to its local 
type, and succeed if such coercion is possible (as per generalization).

However, what if one of the apps want to be more precise, and not want 
to rely on wildcards? Can it not map the schema URI to a locally defined 
  (and more precise) schema?

By this, I'm not advocating a magic and unknown world where no App has 
as idea of what's flowing through. I'm just debating the possibility of 
such "local" decisions. The same applies to constraints too.


> properties, and a processing environment just chooses the ones their
> interested in (although they may assign new properties to the object;
> granted, the types of such properties could be changed by the assigning
> party, but I think those are a minority).


An app may choose to validate what it is interested in and not worry 
about the rest, still adhearing to a common schema. This is fine, expect 
when I consider change propagation. When the common schema changes, each 
app will have to update its schemas (can be painful, sometimes) even 
though it may not really depend on the changes. If I add data binding 
(from this list, I see that data binding is gaining popularity) to this, 
I see more troubles. Now, with each change, each app will have to update 
its data binding classes (that is compile, build, test, stage, and 
deploy) for each change. (Makes me wonder where the "X" in the XML has 
gone).

I don't know if these issues are realistic, and I'm looking for 
experiences from other people in this group.

Subbu