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Posted to dev@lucene.apache.org by "Michael McCandless (JIRA)" <ji...@apache.org> on 2009/07/06 21:45:14 UTC
[jira] Commented: (LUCENE-1522) another highlighter
[ https://issues.apache.org/jira/browse/LUCENE-1522?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12727728#action_12727728 ]
Michael McCandless commented on LUCENE-1522:
--------------------------------------------
Is it possible to decouple this issue from LUCENE-1448 (whose latest patch is quite old and no longer applies and may not make it into 2.9)? Ie, is it only the unit tests that rely on this fix to pass (because they test multi-valued fields)?
> another highlighter
> -------------------
>
> Key: LUCENE-1522
> URL: https://issues.apache.org/jira/browse/LUCENE-1522
> Project: Lucene - Java
> Issue Type: Improvement
> Components: contrib/highlighter
> Reporter: Koji Sekiguchi
> Assignee: Michael McCandless
> Priority: Minor
> Fix For: 2.9
>
> Attachments: colored-tag-sample.png, LUCENE-1522.patch, LUCENE-1522.patch, LUCENE-1522.patch, LUCENE-1522.patch
>
>
> I've written this highlighter for my project to support bi-gram token stream (general token stream (e.g. WhitespaceTokenizer) also supported. see test code in patch). The idea was inherited from my previous project with my colleague and LUCENE-644. This approach needs highlight fields to be TermVector.WITH_POSITIONS_OFFSETS, but is fast and can support N-grams. This depends on LUCENE-1448 to get refined term offsets.
> usage:
> {code:java}
> TopDocs docs = searcher.search( query, 10 );
> Highlighter h = new Highlighter();
> FieldQuery fq = h.getFieldQuery( query );
> for( ScoreDoc scoreDoc : docs.scoreDocs ){
> // fieldName="content", fragCharSize=100, numFragments=3
> String[] fragments = h.getBestFragments( fq, reader, scoreDoc.doc, "content", 100, 3 );
> if( fragments != null ){
> for( String fragment : fragments )
> System.out.println( fragment );
> }
> }
> {code}
> features:
> - fast for large docs
> - supports not only whitespace-based token stream, but also "fixed size" N-gram (e.g. (2,2), not (1,3)) (can solve LUCENE-1489)
> - supports PhraseQuery, phrase-unit highlighting with slops
> {noformat}
> q="w1 w2"
> <b>w1 w2</b>
> ---------------
> q="w1 w2"~1
> <b>w1</b> w3 <b>w2</b> w3 <b>w1 w2</b>
> {noformat}
> - highlight fields need to be TermVector.WITH_POSITIONS_OFFSETS
> - easy to apply patch due to independent package (contrib/highlighter2)
> - uses Java 1.5
> - looks query boost to score fragments (currently doesn't see idf, but it should be possible)
> - pluggable FragListBuilder
> - pluggable FragmentsBuilder
> to do:
> - term positions can be unnecessary when phraseHighlight==false
> - collects performance numbers
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