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From "Dmitry Goldenberg" <dmitry.goldenb...@weblayers.com>
Subject RE: Wildcard and Fuzzy queries - no best fragments generated - ??
Date Tue, 27 Dec 2005 22:51:07 GMT
Erik,
This is great.  Now, just so I understand how rewrite applies.  Are there specific cases when
the rewrite method should or should not be invoked on the query before it is passed on to
the search method?  Where I'm going with this is, if I have a UI which passes the user query
to the back end, can the back end always call rewrite or not?
 
By looking at the code, it seems that things just get reinterpreted as BooleanQuery's and
such.  I just want to know if there are any pitfalls to watch out for.
 
Thanks again,
- Dmitry

________________________________

From: Erik Hatcher [mailto:erik@ehatchersolutions.com]
Sent: Tue 12/27/2005 12:13 PM
To: java-user@lucene.apache.org
Subject: Re: Wildcard and Fuzzy queries - no best fragments generated - ??




On Dec 27, 2005, at 2:34 PM, Dmitry Goldenberg wrote:
> What do you mean by _rewriting_ the query?  I checked all the 
> classes in the highlighter package and did not see any mention of 
> having to rewrite.

 From Highlighter's package.html in it's javadocs:

<pre>
        IndexSearcher searcher = new IndexSearcher(ramDir);
        Query query = QueryParser.parse("Kenne*", FIELD_NAME, analyzer);
        query = query.rewrite(reader); //required to expand search terms
        Hits hits = searcher.search(query);

        Highlighter highlighter = new Highlighter(this, new QueryScorer
(query));
        for (int i = 0; i &lt; hits.length(); i++)
        {
                String text = hits.doc(i).get(FIELD_NAME);
                TokenStream tokenStream = analyzer.tokenStream(FIELD_NAME, new 
StringReader(text));
                // Get 3 best fragments and seperate with a "..."
                String result = highlighter.getBestFragments(tokenStream, text, 3, 
"...");
                System.out.println(result);
        }
</pre>





> ________________________________
>
> From: Erik Hatcher [mailto:erik@ehatchersolutions.com]
> Sent: Tue 12/27/2005 11:03 AM
> To: java-user@lucene.apache.org
> Subject: Re: Wildcard and Fuzzy queries - no best fragments 
> generated - ??
>
>
>
> You have to _rewrite_ the Query for this to work.  This, I believe,
> is mentioned in the javadocs.
>
> I think you are hijacking a thread with your recent postings.  Please
> create a new message rather than reply to one and change the
> subject.  Thanks.
>
>         Erik
>
>
> On Dec 27, 2005, at 1:55 PM, Dmitry Goldenberg wrote:
>
>> Hello,
>>
>> While testing my code that integrates the Highlighter class from
>> org.apache.lucene.search.highlight, I found out that for wildcard
>> and fuzzy queries, it generates no best fragments.
>>
>> Any particular reason why that is the case?  Shouldn't the
>> highlighter be able to work just like with any other query and
>> highlight any matching token sequences?  E.g. if I'm searching for
>> lava~, I'd expect it to highlight words like lava, java, etc.  This
>> is the whole point of highlighting, is it not?
>>
>> Thanks,
>> - Dmitry
>>
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>
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>
>
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