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from XML namespaces to RDF URIs

From: Max Voelkel <voelkel@fzi.de>
Date: Fri, 14 Dec 2007 15:26:20 +0100
Message-ID: <1215807900.20071214152620@fzi.de>
To: semantic-web@w3.org, Leo Sauermann <leo.sauermann@dfki.de>
CC: rdf2go-devel <rdf2go-devel@ontoware.org>, Sesame Developer discussion list <sesame-devel@lists.sourceforge.net>

Hi, and thanks Leo!

http://www.w3.org/TR/2004/PR-webarch-20041105/#xml-namespaces says:
For flat namespaces, concatenation is one useful mapping.

*If* namespace URIs that end with a hash (“#”) are chosen, then simple
concatenation of the namespace URI and the local name creates a URI for a
secondary resource (the identified term). This technique is used for many
[RDFXML] namespaces.
*If not* ... the document says nothing.

LS> if in doubt, read the jena code, they are the reference impl anyway:

LS>    24     /**
LS>    25      * The XSD namespace. This is the real XML Schema namespace
LS>    26      * and so lacks the RDF-friendly # character.
LS>    27      * @deprecated in order to transition to RDF-friendly version replaced by {@link #getURI()}
LS>    28      */
LS>    29     public static String NS = XSDDatatype.XSD;

LS> http://jena.cvs.sourceforge.net/jena/jena2/src/com/hp/hpl/jena/vocabulary/XSD.java?revision=1.12&view=markup

LS>    31     /**
LS>    32      * The RDF-friendly version of the XSD namespace
LS>    33      * with trailing # character.
LS>    34      */
LS>    35     public static String getURI() { return NS + "#"; }
LS>    36 
This  means,  the  Jena-people  re-refined  the  concatenation  rules  for *this
particular*  namespace.  For  semantic  web  to work, all other RDF implementors
should choose the same way.

It would be nice to find a document from W3C that says:

uri(ns,localname) =
  if (ns.endsWith("#") or ns.endsWith("/"))
    return ns + localname
    return ns + "#" + localname

Kind Regards,
       Max Völkel
       voelkel@fzi.de | www.Xam.de
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Received on Friday, 14 December 2007 14:26:40 UTC

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