a.schrijvers at hippo
Jul 30, 2007, 7:12 AM
Post #2 of 4
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RE: Indexing/Analyzer question - case-insensitive "contains" search
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Hello,
> Hi everyone,
>
> I told you I'd be back with more questions! :-)
> Here is my situation. In my application, the field to be searched is
> selected via a drop-down box. I want my searches to basically
> be "contains"
> searches - I take what the user typed in, put a wildcard
> character at the
> beginning and end, and put that in a WildcardQuery with the
> selected field.
> In simple cases, this works great.
It does sound very strange to me, to default to a WildCardQuery! Suppose I am looking for "bold", I am getting hits for "old".
IMO, you should move the WildcardQuery and just use a simple QueryParser (with the analyzer you use at indexing time). Your problem below arises from the fact that you construct your search with WildcardQuery(Term t) and t = new Term("field","Joe's");
But, now you are looking for a term that is very likely not to be present in the index, although you idnexed text that contains "Joe's". The StandardAnalyzer() for example would probably split in ' , and ignores the s. If you use queryparser instead of creating your own term, you are save (and you have no problems with case-sensitive either).
If you do not really understand why it works like this, it might be good to play around with luke: open your index with luke, go to plugins tab, and put in some text and see how it is tokenized with some sample analyzers.
Regards Ard
>
> But, the StandardAnalyzer and SimpleAnalyzer is removing some
> characters I
> need. For example, one of my objects has a name of "Joe's
> Devices". If I
> search for "Joe's", it doesn't work, because the apostrophe
> is stripped out.
> I tried using the KeywordAnalyzer, which keeps the string
> intact, but then
> won't my searches be case-sensitive? This is easy to fix of course by
> calling toLowerCase() on the text when it is indexed, but
> then later when
> retrieved from the index to be displayed in the search results, "Joe's
> Devices" is displayed as "joe's devices". Is there anything I
> can do here
> short of putting two copies of the name in the document - one
> indexed/not
> stored ("joe's devices"), and one stored/not indexed("Joe's
> Devices") ? Or
> can I accomplish this case-insensitive "contains" search some
> other way -
> would I have to write a custom Analyzer, or something?
>
> Thanks in advance!
>
> --
> Joe Attardi
> jattardi [at] gmail
> http://thinksincode.blogspot.com/
>
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