On 07/07/11 08:27, [email protected] wrote:
Hi,
I am a beginner for Semantic Web and currently working with JENA. I came
across the attached file FOAFFriends.rdf that could be read into a Model
with the following statement:
*private**void*populateFOAFFriends(){
_friends= ModelFactory./createOntologyModel/();
InputStream inFoafInstance =
FileManager./get/().open("Ontologies/FOAFFriends.rdf");
_friends.read(inFoafInstance,/defaultNameSpace/);
it's not the default namespace - it's the base URI. The base comes from
1/ xmlbase declaration (nestable)
2/ The declared one
3/ where it's read from if appropriate and meaningful.
See RFC 3986 section 5.
Any relative URI wil be resolved against the base URI as part of parsing.
}
Also, here the defaultNameSpace is:
*static*String /defaultNameSpace/=
http://semwebprogramming.org/2009/ont/chp2#
I have the following question:
The attached file has declarations such as rdf:ID=”me”. I believe from
my reading that if there is rdf:ID declaration in a RDF document, then
it should also contain xml:base declaration, but the file is missing
this declaration. So, how is JENA successfully able to read the RDF
file?
The base URI is provided externally to
Model read(InputStream in, String base)
Where does it get the xml:base declaration from to determine the
complete URI of “me”? Does it do something with the defaultnamespace?
If you say defaultnamespace to be the xml:base, then my question would
be that the xml:base should not contain the # symbol at the end but the
declaration here for defaultnamespace does. How do you justify this please?
Justify?
It's part of the standard process for URI resolution (RFC 3986).
http://semwebprogramming.org/2009/ont/chp2#
if in HTML you had <a href="foo"> you'd expect
http://semwebprogramming.org/2009/ont/foo
right?
if in HTML you had <a href="#bar"> you'd expect
http://semwebprogramming.org/2009/ont/chp2#bar
It's not a simple concatenate.
rdf:ID="me" => a relative URI of #me because it's defined to be that:
http://www.w3.org/TR/rdf-syntax-grammar/#section-Syntax-ID-xml-base
Resolve "#me" with base http://semwebprogramming.org/2009/ont/chp2# and
you get
http://semwebprogramming.org/2009/ont/chp2#me
(there's no double #).
A quick reply would be highly appreciated.=
Thanks
With Regards,
Abhishek S
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