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Message-ID: <934603306.1255117171276.JavaMail.jira@brutus>
Date: Fri, 9 Oct 2009 12:39:31 -0700 (PDT)
From: "Chas Emerick (JIRA)" <jira@apache.org>
To: java-dev@lucene.apache.org
Subject: [jira] Commented: (LUCENE-1822) FastVectorHighlighter:
 SimpleFragListBuilder hard-coded 6 char margin is too naive
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    [ https://issues.apache.org/jira/browse/LUCENE-1822?page=3Dcom.atlassia=
n.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=3D127=
64168#action_12764168 ]=20

Chas Emerick commented on LUCENE-1822:
--------------------------------------

Thank you for the patch.  I agree, the context surrounding each fragment co=
uld definitely be improved.

> FastVectorHighlighter: SimpleFragListBuilder hard-coded 6 char margin is =
too naive
> -------------------------------------------------------------------------=
---------
>
>                 Key: LUCENE-1822
>                 URL: https://issues.apache.org/jira/browse/LUCENE-1822
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: contrib/*
>    Affects Versions: 2.9
>         Environment: any
>            Reporter: Alex Vigdor
>            Priority: Minor
>         Attachments: LUCENE-1822.patch
>
>
> The new FastVectorHighlighter performs extremely well, however I've found=
 in testing that the window of text chosen per fragment is often very poor,=
 as it is hard coded in SimpleFragListBuilder to always select starting 6 c=
haracters to the left of the first phrase match in a fragment.  When select=
ing long fragments, this often means that there is barely any context befor=
e the highlighted word, and lots after; even worse, when highlighting a phr=
ase at the end of a short text the beginning is cut off, even though the en=
tire phrase would fit in the specified fragCharSize.  For example, highligh=
ting "Punishment" in "Crime and Punishment"  returns "e and <b>Punishment</=
b>" no matter what fragCharSize is specified.  I am going to attach a patch=
 that improves the text window selection by recalculating the starting marg=
in once all phrases in the fragment have been identified - this way if a si=
ngle word is matched in a fragment, it will appear in the middle of the hig=
hlight, instead of 6 characters from the beginning.  This way one can also =
guarantee that the entirety of short texts are represented in a fragment by=
 specifying a large enough fragCharSize.

--=20
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