thank you 2010/6/2 Rebecca Watson <bec.wat...@gmail.com>: > Hi Li Li > > If you want to support some query types and not others you should > overide/extend the queryparser so that you throw an exception / makes > a different query type instead. > > Similarity doesn't do the actual scoring, it's used by the Query > classes (actually the Scorer implementation used by the Query) > to get tf / idf scores. So scoring is done by the Query types themselves > (the Weight/Scorer classes used by the Query). So sometimes > you change/extend Similarity to affect scoring and sometimes you > need to change/extend the Query/Scorer/Weight classes etc. > Luckily though, there are already some Query types that boost > scores if the terms are closer -- the SpanQuery query types do this. > > You will either have to write your own queryparser (to convert query string > to the Query object(s) required, > or you could use e.g. the Surround queryparser supports specifying > SpanQuery queries via user-entered text: > http://www.lucidimagination.com/blog/2009/02/22/exploring-query-parsers/ > > look in the lucene contrib/surround package for the surround queryparser. > > I've messed about with using SpanQuery classes a bit and people report > that they are slower - which is true because they use a lot of extra > info to perform their matching/scoring -- but they are still easily > sub-second over most > queries / reasonable sized doc collection > -- and they only get a lot slower if you have terms that occur very frequently > in the document collection you are searching. > So if you are removing stop words etc you shouldn't have too > many problems efficiency wise. > > hope that helps, > > bec :) > > On 1 June 2010 22:07, Li Li <fancye...@gmail.com> wrote: >> I want to only support boolean or query(as many search engine do). But >> I want to boost document whose terms are closer. >> e.g. the query terms are 'apache lucene' >> doc1 apache has many projects such as lucene >> doc2 The Apache HTTP Server Project is an effort to develop and >> maintain an ... Lucene is a ..... >> I want to give doc1 more boost. >> So I need a place where I can get all position information >> How to extend Similarity to achieve this? >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org >> For additional commands, e-mail: java-user-h...@lucene.apache.org >> >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org > >
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