potential changes to VODataService!

[Ray Plante]

Hi Guy and Kevin,

Thanks for your comments.  Since you are among the few that have 
responded, they carry a lot of weight.

I want probe your situations a bit more.  Below, I refer to your 
application.  For Guy, I'm refering to the software you mentioned.  For 
Kevin, I mean your registries.  Keep in mind that the changes being 
proposed are such that existing instance documents will still be valid.

1.  Does your application do validation?
2.  Do you keep and use a copy of the schema local to your application or
     does your application download it transparently from www.ivoa.net?
3.  Do you use an XML-binding tool such as JAXB?
4.  Do you tolerate VOResource records that invoke extensions that were
     previously unknown to you?
5.  If an incoming VOResource record contained elements from a known
     schema that you were not expecting (i.e. it looks invalid to you),
     would your application break?    (This might occur, for example, if
     you are using JAXB or rely on elements appearing in a particular
     order).
6.  Can your application be upgraded simply by retrieving the latest
     version of the schema, or is there more involved?

On Thu, 7 Jun 2007, KevinBenson wrote:
> Also note I am thinking this might break one of your rules 
> you mentioned on Nov 21 'Version Numbers on XMLSchemata' see this url: 
> http://www.ivoa.net/forum/registry/0611/1760.htm

I assume that you are refering to rule #2.

   2.  backward compatible changes that should not invalidate/break
       existing instances or applications

These would not invalidate existing instances.  My questions above are 
about examining the effect on your applications.

Not updating the namespace represent a low-to-middle ground of disruption. 
When you change the namespace, either everyone is highly disrupted 
upgrading their records and applications or no one is disrupted, because 
the change is not adopted.  If you don't change the namespace and the 
syntax is backward-compatible to the instance documents, then only some 
subset of applications are affected.

thanks!
Ray