Re: *term search

[sergiu gordea]

[EMAIL PROTECTED] wrote:
.. and here is the way to do it:
(See attached file: SUPPOR~1.RAR)
 

Hi all,
I got from iouli the solution to enable prefix queries (*term). In fact 
you can find the solution in
lucene source, in QueryParser.jj is said in a comment how to  enable 
prefix queries.

I did so ... but I found a lot of bugs. If you  define WildTerm as
| <WILDTERM:  (<_TERM_CHAR> | ( [ "*", "?" ] ))* >
a lot of  constructions will be validated, and you will get a lot of 
errors ...
for example "----" and "+++++" are considered valid, * is considered 
valid, and they generate TooManyBooleanClausesExceptions,

I' not very good in creating regular expressions but I succesfully use 
the following construction ..

| <WILDTERM:  (<_TERM_START_CHAR> (<_TERM_CHAR> | ( [ "*", "?" ] ))* )
                   | ( [ "*", "?" ] <_TERM_START_CHAR> (<_TERM_CHAR> | 
( [ "*", "?" ] ) )* ) >

Can anyone improve the construction and update the comment in 
QueryParser.jj?

 Thanks a lot,
 Sergiu

                                                                                                         
                     Erik Hatcher                                                                        
                     <[EMAIL PROTECTED]        To:       "Lucene Users List"                              
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                     08.09.2004 12:46         Subject:  Re: *term search                                 
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On Sep 8, 2004, at 6:26 AM, sergiu gordea wrote:
 

I want to discuss a little problem, lucene doesn't support *Term like
queries.
   

First of all, this is untrue.  WildcardQuery itself most definitely
supports wildcards at the beginning.
 

I would like to use "*schreiben".
   

The dilemma you've encountered is that QueryParser prevents queries
that begin with a wildcard.
 

So my question is if there is a simple solution for implementing the
funtionality mentioned above.
Maybe subclassing one class and overwriting some methods will sufice.
   

It will require more than that in this case.  You will need to create a
custom parser that allows the grammar you'd like.  Feel free to use the
JavaCC source code to QueryParser as a basis of your customizations.
            Erik
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