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https://issues.apache.org/jira/browse/JENA-1313?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15953688#comment-15953688
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Andy Seaborne commented on JENA-1313:
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Err - it does not use argument 'value'.
Did you mean to calculate the key given the value?
(aside - cache the Collator - a one slot cache will catch the same language
case).
Functionally - looks OK because lang is the leading part of the string.
Performance - expensive because of {{Hex.encodeHexString(key)}} and string
{{+}}. This operation is going to be called on every item sorted. Using
{{byte[]}} directly is cheaper.
Which method are you thinking of changing? We can probably cut through the
machinary if the result is only used locally. Saves needing to add
{{NodeValueByteArray}}.
If it's {{NodeValue::compare(NodeValue nv1, NodeValue nv2, boolean
sortOrderingCompare)}}, there are the cases of:
VALUE_LANG / VALUE_LANG
VALUE_LANG / VALUE_STRING
VALUE_STRING / VALUE_LANG
(Might be worth adding to {{NodeValue::classifyValueOp(NodeValue, NodeValue}}
not write out in full in {{NodeValue::compare}}.)
> Language-specific collation in ARQ
> ----------------------------------
>
> Key: JENA-1313
> URL: https://issues.apache.org/jira/browse/JENA-1313
> Project: Apache Jena
> Issue Type: Improvement
> Components: ARQ
> Affects Versions: Jena 3.2.0
> Reporter: Osma Suominen
>
> As [discussed|http://markmail.org/message/v2bvsnsza5ksl2cv] on the users
> mailing list in October 2016, I would like to change ARQ collation of literal
> values to be language-aware and respect language-specific collation rules.
> This would probably involve changing at least the
> [NodeUtils.compareLiteralsBySyntax|https://github.com/apache/jena/blob/master/jena-arq/src/main/java/org/apache/jena/sparql/util/NodeUtils.java#L199]
> method.
> It currently sorts by lexical value first, then by language tag. Since the
> collation order needs to be stable across all possible literal values, I
> think the safest way would be to sort by language tag first, then by lexical
> value according to the collation rules for that language.
> But what about subtags like {{@en-US}} or {{@pt-BR}}? Can they have different
> collation rules than the main language? It would be a bit strange if all
> {{@en-US}} literals sorted after {{@en}} literals...
> It would be good to check how Dydra does this and possibly take the same
> approach. See the message linked above for further backgound.
> I've been talking with [~kinow] about this and he may be interested in
> implementing it.
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