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[apologizes if this appears twice, this is a resend after a mail problem] Hi, Over the weekend I was reading through the XML Catalog specification [1] and toying with the implementation of a catalog resolver available through the Apache xml-commons project [2]. I was surprised about the way that system and public identifiers are handled, and thought I'd check in here to see whether I'm misinterpreting the spec (likely!) or could find some rationale for the behaviour. Specifically, it would seem that System Identifiers are the preferred way of accessing a catalog, and Public Identifiers play second fiddle. Granted the spec does include a "preferred" mode for accessing the catalog but according to Section 7.1.2 of the spec if a system identifier can be matched in the catalog then that will always be used; an accompanying public identifier is only used as a fallback if the system id doesn't match (or is unavailable) and the prefer setting is "public". So public ids are only useful if the system identifier isn't available. Given that you have to provide both in XML, public ids seem pretty redundant. Toying with the command-line resolver application shows behaviour consistent with this reading. Everything I've read up to now set me up to expect the following: that Public Ids would be preferred and that System Ids would be the fallback. What am I missing? [1]. https://www.oasis-open.org/committees/entity/specs/cs-entity-xml-catalogs-1.0.html [2]. http://xml.apache.org/commons/ [3]. https://www.oasis-open.org/committees/entity/specs/cs-entity-xml-catalogs-1.0.html#s.ext.resx
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