potential changes to VODataService!
rplante at poplar.ncsa.uiuc.edu
Thu Jun 7 07:28:22 PDT 2007
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
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:
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.
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