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Re: [wtp-dev] XML Catalog - namespaces or schemaLocations ... or both

Paul Fullbright wrote:

The XML Catalog specification can be found here:
Yes, I tried to digest it, without much luck. There seems to be a lot of circular definition, such as: "The system entry indicates that an entity manager must use the associated URI reference to locate the replacement text for an entity with the specified /system identifier/." I'm still unclear what the "system" term is referring to. I'm hoping for a layman's "use the uri tag /here/, the public tag /here/, and the system tag /here/ ..." The extension point description doesn't seem to help me much in this regard. It *seems* to me that public and system are pre-XML Schema terms, and since we are not having to deal with anything other than schemas re: JPA (and I should note that my pre-XML Schema knowledge is ... absent), I might be able to safely ignore those.

A lot of this terminology is a carry over from the DTD. In DTD there are two types of entries:

System - which is a private local version of the grammar.
Public - an externally referenced grammar.
System Identifier - (think of this as where the item can be found, it could be a url.)

An example of a System Identifier is:

|<!DOCTYPE html SYSTEM "";>

|Where the items in between the quotes is the System Identifier.

An article has a pretty go description of this:

The SYSTEM identifier tells the XML parser where to find the DTD file on the system. An optional PUBLIC identifier can specify another string for the parser to use when locating a DTD file. These usually use a string similar to the following, which avoids any system-specific information to make the document more portable across different systems.

I'll have to think on your example, but I know that you can't use the XML Catalog to do what you want. The namespace would be identified twice, and you can't have duplicate entries, as the key is the namespace name.


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