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https://issues.apache.org/jira/browse/JENA-1556?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16513822#comment-16513822
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ASF GitHub Bot commented on JENA-1556:
--------------------------------------
Github user xristy commented on a diff in the pull request:
https://github.com/apache/jena/pull/436#discussion_r195736987
--- Diff:
jena-text/src/main/java/org/apache/jena/query/text/TextIndexLucene.java ---
@@ -316,6 +326,13 @@ protected Document doc(Entity entity) {
if (this.isMultilingual) {
// add a field that uses a language-specific
analyzer via MultilingualAnalyzer
doc.add(new Field(e.getKey() + "_" + lang,
(String) e.getValue(), ftText));
+ // add fields for any defined auxiliary indexes
+ List<String> auxIndexes = Util.getAuxIndexes(lang);
+ if (auxIndexes != null) {
--- End diff --
``auxIndexes.get(tag)`` will return null if ``tag`` has no auxiliary
indexes defined - which is not an unusual case.
As I look at ``Util.getAuxIndexes`` I unnecessarily return an empty list
that then does no work in the guarded ``for`` loop. I'm changing to ``null`` in
the case of a ``null`` or empty ``tag``.
> text:query multilingual enhancements
> ------------------------------------
>
> Key: JENA-1556
> URL: https://issues.apache.org/jira/browse/JENA-1556
> Project: Apache Jena
> Issue Type: New Feature
> Components: Text
> Affects Versions: Jena 3.7.0
> Reporter: Code Ferret
> Assignee: Code Ferret
> Priority: Major
> Labels: pull-request-available
>
> This issue proposes two related enhancements of Jena Text. These enhancements
> have been implemented and a PR can be issued.
> There are two multilingual search situations that we want to support:
> # We want to be able to search in one encoding and retrieve results that may
> have been entered in other encodings. For example, searching via Simplified
> Chinese (Hans) and retrieving results that may have been entered in
> Traditional Chinese (Hant) or Pinyin. This will simplify applications by
> permitting encoding independent retrieval without additional layers of
> transcoding and so on. It's all done under the covers in Lucene.
> # We want to search with queries entered in a lossy, e.g., phonetic,
> encoding and retrieve results entered with accurate encoding. For example,
> searching vis Pinyin without diacritics and retrieving all possible Hans and
> Hant triples.
> The first situation arises when entering triples that include languages with
> multiple encodings that for various reasons are not normalized to a single
> encoding. In this situation we want to be able to retrieve appropriate result
> sets without regard for the encodings used at the time that the triples were
> inserted into the dataset.
> There are several such languages of interest in our application: Chinese,
> Tibetan, Sanskrit, Japanese and Korean. There are various Romanizations and
> ideographic variants.
> Encodings may not normalized when inserting triples for a variety of reasons.
> A principle one is that the {{rdf:langString}} object often must be entered
> in the same encoding that it occurs in some physical text that is being
> catalogued. Another is that metadata may be imported from sources that use
> different encoding conventions and we want to preserve that form.
> The second situation arises as we want to provide simple support for phonetic
> or other forms of lossy search at the time that triples are indexed directly
> in the Lucene system.
> To handle the first situation we introduce a {{text}} assembler predicate,
> {{text:searchFor}}, that specifies a list of language tags that provides a
> list of language variants that should be searched whenever a query string of
> a given encoding (language tag) is used. For example, the following
> {{text:TextIndexLucene/text:defineAnalyzers}} fragment :
> {code:java}
> [ text:addLang "bo" ;
> text:searchFor ( "bo" "bo-x-ewts" "bo-alalc97" ) ;
> text:analyzer [
> a text:GenericAnalyzer ;
> text:class "io.bdrc.lucene.bo.TibetanAnalyzer" ;
> text:params (
> [ text:paramName "segmentInWords" ;
> text:paramValue false ]
> [ text:paramName "lemmatize" ;
> text:paramValue true ]
> [ text:paramName "filterChars" ;
> text:paramValue false ]
> [ text:paramName "inputMode" ;
> text:paramValue "unicode" ]
> [ text:paramName "stopFilename" ;
> text:paramValue "" ]
> )
> ] ;
> ]
> {code}
> indicates that when using a search string such as "རྡོ་རྗེ་སྙིང་"@bo the
> Lucene index should also be searched for matches tagged as {{bo-x-ewts}} and
> {{bo-alalc97}}.
> This is made possible by a Tibetan {{Analyzer}} that tokenizes strings in all
> three encodings into Tibetan Unicode. This is feasible since the
> {{bo-x-ewts}} and {{bo-alalc97}} encodings are one-to-one with Unicode
> Tibetan. Since all fields with these language tags will have a common set of
> indexed terms, i.e., Tibetan Unicode, it suffices to arrange for the query
> analyzer to have access to the language tag for the query string along with
> the various fields that need to be considered.
> Supposing that the query is:
> {code:java}
> (?s ?sc ?lit) text:query ("rje"@bo-x-ewts)
> {code}
> Then the query formed in {{TextIndexLucene}} will be:
> {code:java}
> label_bo:rje label_bo-x-ewts:rje label_bo-alalc97:rje
> {code}
> which is translated using a suitable {{Analyzer}},
> {{QueryMultilingualAnalyzer}}, via Lucene's {{QueryParser}} to:
> {code:java}
> +(label_bo:རྗེ label_bo-x-ewts:རྗེ label_bo-alalc97:རྗེ)
> {code}
> which reflects the underlying Tibetan Unicode term encoding. During
> {{IndexSearcher.search}} all documents with one of the three fields in the
> index for term, "རྗེ", will be returned even though the value in the fields
> {{label_bo-x-ewts}} and {{label_bo-alalc97}} for the returned documents will
> be the original value "rje".
> This support simplifies applications by permitting encoding independent
> retrieval without additional layers of transcoding and so on. It's all done
> under the covers in Lucene.
> Solving the second situation will simplify applications by adding appropriate
> fields and indexing via configuration in the
> {{text:TextIndexLucene/text:defineAnalyzers}}. For example, the following
> fragment
> {code:java}
> [ text:addLang "zh-hans" ;
> text:searchFor ( "zh-hans" "zh-hant" ) ;
> text:auxIndex ( "zh-aux-han2pinyin" ) ;
> text:analyzer [
> a text:DefinedAnalyzer ;
> text:useAnalyzer :hanzAnalyzer ] ;
> ]
> [ text:addLang "zh-hant" ;
> text:searchFor ( "zh-hans" "zh-hant" ) ;
> text:auxIndex ( "zh-aux-han2pinyin" ) ;
> text:analyzer [
> a text:DefinedAnalyzer ;
> text:useAnalyzer :hanzAnalyzer ] ;
> ]
> [ text:addLang "zh-latn-pinyin" ;
> text:searchFor ( "zh-latn-pinyin" "zh-aux-han2pinyin" ) ;
> text:analyzer [
> a text:DefinedAnalyzer ;
> text:useAnalyzer :pinyin ] ;
> ]
> [ text:addLang "zh-aux-han2pinyin" ;
> text:searchFor ( "zh-latn-pinyin" "zh-aux-han2pinyin" ) ;
> text:analyzer [
> a text:DefinedAnalyzer ;
> text:useAnalyzer :pinyin ] ;
> text:indexAnalyzer :han2pinyin ;
> ]
> {code}
> defines language tags for Traditional, Simplified, Pinyin and an _auxiliary_
> tag {{zh-aux-han2pinyin}} associated with an {{Analyzer}}, {{:han2pinyin}}.
> The purpose of the auxiliary tag is to define an {{Analyzer}} that will be
> used during indexing and to specify a list of tags that should be searched
> when the auxiliary tag is used with a query string.
> Searching is then done via multi-encoding support discussed above. In this
> example the {{Analyzer}}, {{:han2pinyin}}, tokenizes strings in {{zh-hans}}
> and {{zh-hant}} as the corresponding pinyin so that at search time a pinyin
> query will retrieve appropriate triples inserted in Traditional or Simplified
> Chinese. Such a query would appear as:
> {code}
> (?s ?sc ?lit ?g) text:query ("jīng"@zh-aux-han2pinyin)
> {code}
> The auxiliary field support is needed to accommodate situations such as
> pinyin or sound-ex which are not exact, i.e., one-to-many rather than
> one-to-one as in the case of Simplified and Traditional.
> {{TextIndexLucene}} adds a field for each of the auxiliary tags associated
> with the tag of the triple object being indexed. These fields are in addition
> to the un-tagged field and the field tagged with the language of the triple
> object literal.
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