Hi all, As I mentioned during the XML phone conference, I've a few questions about the current XML rendering. I don't think they're too important (not show-stoppers), but they might be worth raising. 1. In the Base type we define a Validity as an int 0..1, I suspect that this is really a boolean (which is a base-type). In XML-Schema, the boolean type can be either "true", "false", "0" or "1" (with true/false is the canonical form). So, if we switch this to a boolean, we would allow "true" and "false" as valid entries. If we don't want this, we can contract the boolean so it only accepts "0" or "1" (I think), but is a boolean none-the-less. Also, perhaps this attribute should be isValid (so something that maps more directly to a boolean), rather than Validity (which should take values like is-valid or is-not-valid). 2. XML nillable vs Validity XML Schema allows entries to be "nillable"; that is, the corresponding point in the XML tree can be empty, even if has required content. For example, AdminDomain has a required child element: ID. <Grid> <AdminDomain> <ID>CNAF</ID> <!-- more here --> </AdminDomain> </Grid> If AdminDomain was nillable, the following <Grid> <AdminDomain/> </Grid> would still be valid (i.e., pass the XSD validation). The current XML Schema has nillable switched off for all elements. Do we want to express invalid objects by simply publishing empty objects? Does it make sense to publish an AdminDomain with validity=false and a ComputingService with validity=true ? I'm not particularly advocating this, but rather posing it as an interesting question. See also (a random Google find): http://www.stylusstudio.com/xmldev/200309/post20390.html 3. Adding "unknown" as a place-holder enumeration value for all enumeration types. Do we want to include an "unknown" (or similar) value for the enumerations? This would be to satisfy the two use-cases described in Appendix A. This is perhaps not an XML-specific question, though. Cheers, Paul.
Hi Paul, Paul Millar wrote:
1. In the Base type we define a Validity as an int 0..1,
Here there is probably a misunderstanding. The validity is actually a UInt64 in the latest spec. It represents the number of seconds that the information is considered relevant by the info provider expressed in s. In the current XSD, the data type is int (to be updated).
2. XML nillable vs Validity
XML Schema allows entries to be "nillable"; that is, the corresponding point in the XML tree can be empty, even if has required content. For example, AdminDomain has a required child element: ID.
<Grid> <AdminDomain> <ID>CNAF</ID> <!-- more here --> </AdminDomain> </Grid>
If AdminDomain was nillable, the following
<Grid> <AdminDomain/> </Grid>
would still be valid (i.e., pass the XSD validation).
The current XML Schema has nillable switched off for all elements.
Do we want to express invalid objects by simply publishing empty objects? Does it make sense to publish an AdminDomain with validity=false and a ComputingService with validity=true ?
I'm not particularly advocating this, but rather posing it as an interesting question. See also (a random Google find):
maybe we should rename Validity to Expire? :) anyway, given the today discussion, we should probably not add nillable elements. The mandatory attributes should be published using the values mentioned in the appendix. What do you think of it?
3. Adding "unknown" as a place-holder enumeration value for all enumeration types.
Do we want to include an "unknown" (or similar) value for the enumerations? This would be to satisfy the two use-cases described in Appendix A.
This is perhaps not an XML-specific question, though.
ok, this is something that could be done. Let's listen to other opinions. Sergio
Cheers,
Paul. _______________________________________________ glue-wg mailing list glue-wg@ogf.org http://www.ogf.org/mailman/listinfo/glue-wg
-- Sergio Andreozzi INFN-CNAF, Tel: +39 051 609 2860 Viale Berti Pichat, 6/2 Fax: +39 051 609 2746 40126 Bologna (Italy) Web: http://www.cnaf.infn.it/~andreozzi
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Paul Millar -
Sergio Andreozzi