Announcement of work on ODF 1.2 metadata feature adoptions

[Svante Schubert <Svante.Schubert@Sun.COM>]

After the review of our RDF metadata feature by the inventors of RDF, 
the W3C Semantic Web Interest Group (SWIG), two weeks ago at the TPAC 
2008, I received a lot of positive feed-back.

Nevertheless even good features have potential of improvement, therefore 
I have three subjects I am working on to bring the ODF RDF feature to 
close perfection, driven by the feed-back from SWIG and Tim Berners-Lee 
especially.

Here the rough descriptions of the three topics, a detailed proposal 
will follow:

1)
We are using RDFa attriubtes and the W3C RDFa spec [1] has received 
Recommendation status less than 3 weeks ago.
The usage of the four RDFa elements can now be done accordingly to the 
W3C spec. Even with XHTML namespace due to the XHTML modularization 
statement that all no namespace XHTML attributes can rather use the 
XHTML namespace [2].
The usage of the attribute definitions from the original spec will give 
us furthermore the abbreviation mechanism as compact URIs (CURI), which 
can help a lot in large spreadsheets.
Other RDFa features, e.g. Chaining [3], are rather meant for DOM 
applications and will not apply to ODF applications.

2)
Although ODF applications do not need this for themselves, we should 
help other none-ODF RDF applications to receive the RDF graphs from our 
package, to let ODF become successful.
For this reason I will work on two XSLT transformations (according to 
the W3C GRDDL standard [4]) that will help foreign users/crawlers to 
extract RDF data from ODF.
My basic idea is that styles.xml and content.xml will receive a 
reference to one XSLT stylesheet based on [5] to extract RDFa and 
another XSLT for the meta.xml, making RDFa statements from every 
sub-element of office:meta (e.g. <document> meta:creation-date 
"2007-05-10T18:18:56".).
ODF application should ignore these GRDDL attributes located at the root 
element, with an URL pointing to the stylesheet somewhere hosted at 
OASIS. These stylesheets are only guidance for foreign applications.

3)
The SWIG where rather puzzled by the usage of generated URNs in the 
ODF/RDF examples. The web lives from URLs, so will be the Semantic Web. 
Aside of this, there is a design rule in the "Architecture of the World 
Wide Web" not to create alias [6]. Everybody strongly suggested to use 
relative URLs within the package and to reference to the resources 
within the package with URLs.
Unfortunately that triggers the problem of referencing from outside 
inside the ODF package by URLs, when making these relative URLs absolute.

In general there are three possibilities:
a) Using an URL that thinks of a package similar as an directory
b) A package schema similar to 'jar:' that has never been standardized
c) Create own fragment identifier for our mimetypes.

Currently I believe a) & b) are valid and desired options, but out of 
the scope of our TC (not to mention the time frame), therefore I have 
asked to discuss this general package related problem at the W3C Web 
Technical Architecture Working group (further details at [7] and thread).

I am currently at the OpenOffice.org Conference in Beijing, I would be 
happy to discuss these topics with you face to face, but would ask the 
group not to start a larger discussion on these topics until a detailed 
proposal is given to the TC to base a discussion on.

Regards,
Svante

[1] http://www.w3.org/TR/rdfa-syntax/
[2] 
http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_commonatts
[3] http://www.w3.org/TR/rdfa-syntax/#sec_5.3.
[4] http://www.w3.org/TR/grddl/
[5] http://www.w3.org/2008/07/rdfa-xslt
[6] http://www.w3.org/TR/webarch/#avoid-uri-aliases
[7] http://lists.w3.org/Archives/Public/www-tag/2008Oct/0126.html


Sun Microsystems GmbH           Svante Schubert
Nagelsweg 55                    Software Engineer
20097 Hamburg                   StarOffice / OpenOffice.org Development
Germany                         Phone: +49(0)40 236 46 500
http://www.sun.com              Svante.Schubert@sun.com

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