Fwd: Re: [Sesame] RDF-1.1 updates

[Sergio Fernández <se...@salzburgresearch.at>]

very relevant for us

-------- Original Message --------
Subject: Re: [Sesame] RDF-1.1 updates
Date: Tue, 27 Aug 2013 13:52:40 +1000
From: Peter Ansell <an...@gmail.com>
Reply-To: Sesame discussion list <se...@lists.sourceforge.net>
To: sesame-devel@googlegroups.com <se...@googlegroups.com>, 
Sesame discussion list <se...@lists.sourceforge.net>

(Cross-posting to sesame-general to get feedback)

There is a Pull Request at BitBucket to update Sesame towards RDF-1.1.
Any and all reviewers of the changes are welcome.

 
https://bitbucket.org/openrdf/sesame/pull-request/190/rdf-11-changes-ses-1720-ses-1803-ses-1916/diff

The RDF-1.1 specification is in Last Call until 6 September and it
would be useful to have the necessary changes tested in Sesame before
then to provide feedback to the RDF Working Group.

The Pull Request will complete three of the 7 subtasks for SES-1720,
with the remaining features still to be implemented.

     https://openrdf.atlassian.net/browse/SES-1720

The patch, as it currently stands, will affect backwards compatibility
for the following usage pattern:

     Literal literal = ...
     if(literal.getDatatype() != null)
         ...
     else if(literal.getLanguage() != null)
         // This block will never execute now as there are no plain
literals in RDF-1.1

The solution is to use:

     if(Literals.isTypedLiteral(literal))
         .... // If the literal has a language tag this block will not 
execute
     else if(Literals.isLanguageLiteral(literal))
         // This block will execute as expected

However, the following similar pattern will be unaffected and should
still work as expected in an RDF-1.1 framework:

     Literal literal = ...
     if(literal.getLanguage() != null)
         ...
     else if(literal.getDatatype() != null)
         // This block will still execute properly

Any code that relies on both language and datatype being null will not
execute, as all literals that were RDF-1.0 Plain Literals will now be
RDF-1.1 Typed Literals will the datatype xsd:string.

Cheers,

Peter

On 23/08/2013, Peter Ansell <an...@gmail.com> wrote:
> The RDF-1.1 drafts are in last call until 6 September.
>
> The main changes that we need to implement (and decide on backwards
> compatibility for) to close SES-1720 are to:
>
> 1. Ensure that RDF-1.0 Plain Literals can iternally be treated as
> Typed Literals with the type xsd:string (even if that type does not
> appear in a serialisation).
> 2. Ensure that RDF-1.0 Language Literals can internally be treated as
> Typed Literals, with attached language tags, and with the type
> rdf:LangString internally (serialisations are not likely to concretely
> display this type, and neither should SPARQL Results documents in
> general)
> 3. Ensure that we support BCP-47 Language Tags. Previously we were
> going to get this from the Locale class by updating to Java-7, but we
> will now need to determine a way to backport support to Java-6 easily
> as the Java-7 version bump has been indefinitely postponed.
>
> References:
>
> http://www.w3.org/TR/2013/WD-rdf11-concepts-20130723/#changes
>
> http://www.w3.org/TR/2013/WD-rdf11-concepts-20130723/#section-Graph-Literal
>
> SES-1803 is one possibility for solving 1 and 2, but we could support
> another way without adding a new method to the Literal interface if it
> is cleaner.
>
> SES-1826 is the issue tracking number 3.
>
> I would like if SES-1720 was targeted at 2.8, but I am not sure if we
> can support practical backwards compatibility over the 2.7 to 2.8
> version bump.
>
> Thanks,
>
> Peter
>

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Sergio Fernández
Salzburg Research
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