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https://issues.apache.org/jira/browse/JENA-170?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13160187#comment-13160187
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Henry Story edited comment on JENA-170 at 11/30/11 6:03 PM:
------------------------------------------------------------
It seems to me that xsd:hexBinary would make more sense to store directly as a
blob, and do value matching on. This is because there is really not much
personalisation that one can do with a hexBinary. The numbers have to follow
each other without white space. There can only be white space at the beginning
and end (if at all). I can see that this would be more of an issue with
xsd:base64Binary since that literal can contain newlines in the middle of the
number, and there people may want to keep formatting.
Anyway, is it difficult to add what I now understand is called a D-entailment
regime for xsd:hexBinary to Jena? Is this something I can do as a developer?
http://www.w3.org/TR/sparql11-entailment/#DEntRegime
I am interested in this not just for my own implementations, but also because
we need to specify this behavior carefully in the WebID spec
http://webid.info/spec#verifying-the-webid-claim . We are using SPARQL there to
make it as easy to understand for developers and readers of the Spec as
possible - a spec that we hope will bring a lot of people into the semantic web
community.
was (Author: bblfish):
It seems to me that xsd:hexBinary would make more sense to store directly
as a blob, and do value matching on. This is because there is really not much
personalisation that one can do with a hexBinary. The numbers have to follow
each other without white space. There can only be white space at the beginning
and end (if at all) I can see that this would be more of an issue with
xsd:base64Binary since that literal can contain newlines in the middle of the
number, and there people may want to keep formatting.
Anyway, is it difficult to add what I now understand is called a D-entailment
regime for xsd:hexBinary to Jena? Is this something I can do as a developer?
http://www.w3.org/TR/sparql11-entailment/#DEntRegime
I am interested in this not just for my own implementations, but also because
we need to write the specify this behavior carefully in the WebID spec
http://webid.info/spec#verifying-the-webid-claim
> hexBinary whitespace issue
> --------------------------
>
> Key: JENA-170
> URL: https://issues.apache.org/jira/browse/JENA-170
> Project: Jena
> Issue Type: Bug
> Components: ARQ, Jena, RDF/XML
> Environment: 2.6.4
> Reporter: Henry Story
> Assignee: Andy Seaborne
> Priority: Minor
>
> As I understand, initial and final white spaces in xsd:hexBinary in xml
> should be ignored
> http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#hexBinary
>
> because of the whitespace facet.
> With Jena 2.6.4 this is not the case, as shown by the test below.
> I found that in Clerezza when using the graph api, so this is a problem even
> when one does not use SPARQL.
> Removing the white space solves the proble.
> xsd:hexBinary is already a very fragile encoding. Making it this fragile is
> bound to lead to issues in communication.
> The same is true with the N3 encoding.
> -----------------------------------------------------------------
> hjs@bblfish[0]$ cat q1.sparql
> PREFIX : <http://me.example/p#>
> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
> SELECT ?S WHERE {
> ?S :related "AAAA"^^xsd:hexBinary .
> }
> hjs@bblfish[0]$ cat c1.rdf
> <rdf:RDF xmlns="http://me.example/p#";
> xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";>
> <rdf:Description rdf:about="http://me.example/p#me";>
> <related rdf:datatype="http://www.w3.org/2001/XMLSchema#hexBinary";>
> AAAA
> </related>
> </rdf:Description>
> </rdf:RDF>
> hjs@bblfish[0]$ arq --query=q1.sparql --data=c1.rdf
> -----
> | S |
> =====
> -----
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