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From András Péteri <apet...@b2international.com>
Subject Re: ConjunctionScorer access
Date Thu, 22 Oct 2015 14:50:35 GMT
Going by the example, it looks like you could do something like this:

1) Use the existing field for adding terms with payloads as before
("payload_field");
2) Introduce another field ("excluded_field"), adding only those terms
where you expect a score of zero to be returned (based on the payload);
2) Add MUST clauses for term A and term B in "payload_field", and also
include a MUST_NOT clause matching term A in "excluded_field" to the
BooleanQuery.

The idea is that documents that have both term A and term B in
"payload_field" will not necessarily have term A in "excluded_field" --
only the ones that you don't want to see in the result set.

Regards,
András

On Thu, Oct 22, 2015 at 4:06 PM, Sheng <shengcer@gmail.com> wrote:

> That's the problem right - none of them are public, and even neither is the
> constructor of `ConjunctionScorer`. Moreover, `ConjunctionScorer` needs
> access to list of sub-scorers to emit the doc and score. Information like
> this has to come from the `BooleanWeight`, which is another hack if I want
> to leverage this.
>
> On Thu, Oct 22, 2015 at 9:22 AM, Alan Woodward <alan@flax.co.uk> wrote:
>
> > You should be able to use a FilterScorer that wraps a ConjunctionScorer
> > and overrides score().
> >
> > Alan Woodward
> > www.flax.co.uk
> >
> >
> > On 22 Oct 2015, at 13:43, Sheng wrote:
> >
> > > Thanks for the reply and suggestion. If I search for term A and term B
> > with
> > > a BooleanQuery in Lucene, normally Lucene returns documents that have a
> > > match of both A and B. Now I am using payload to vary the scores w.r.t
> > > search of term A and search of term B, so it is possible for example a
> > > document has both match of term A and term B, but only the score for
> > term A
> > > is 0. In this case, I want Lucene does not return this document  at
> all.
> > > However the internal ConjunctionScorer will just sum up the scores
> > returned
> > > by both subquery of A and B, thus the document has a score > 0 returned
> > by
> > > the BooleanQuery, and therefore it cannot be filtered by a
> > > PositiveScoreOnlyCollector. I know hacking into ConjunctionScorer
> > probably
> > > is too intrusive, but wondering if there is a better way to achieve the
> > > same effect ?
> > >
> > > On Thu, Oct 22, 2015 at 4:13 AM, Uwe Schindler <uwe@thetaphi.de>
> wrote:
> > >
> > >> Hi,
> > >>
> > >> Those are internal classes and not to be extended (not only the
> > >> constructor is pkg-private, the whole class is: https://goo.gl/5WyLYz
> )!
> > >> Scorers follow the delegator pattern. If you want to modify the
> > behaviour
> > >> of a Scorer, create a delegator scorer (e.g. some Filtering Scorer)
> and
> > >> change its behaviour (e.g. filter additional documents,...). This can
> be
> > >> done by a query that filters other querys. E.g. look at
> > ConstantScoreQuery
> > >> or similar queries that wrap other scorers.
> > >>
> > >> Subclassing ConjunctionScorer would bring you nothing because
> internals
> > >> are still private - and that's good.
> > >>
> > >> Uwe
> > >>
> > >> -----
> > >> Uwe Schindler
> > >> H.-H.-Meier-Allee 63, D-28213 Bremen
> > >> http://www.thetaphi.de
> > >> eMail: uwe@thetaphi.de
> > >>
> > >>
> > >>> -----Original Message-----
> > >>> From: Sheng [mailto:shengcer@gmail.com]
> > >>> Sent: Wednesday, October 21, 2015 7:03 PM
> > >>> To: java-user@lucene.apache.org
> > >>> Subject: ConjunctionScorer access
> > >>>
> > >>> It's a bummer Lucene makes the constructor of ConjunctionScorer non-
> > >>> public. I wanted to extend from this class in order to tweak its
> > >> behavior for
> > >>> my use case. Is it possible to change it to protected in future
> > releases
> > >> ?
> > >>
> > >>
> > >> ---------------------------------------------------------------------
> > >> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> > >> For additional commands, e-mail: java-user-help@lucene.apache.org
> > >>
> > >>
> >
> >
>

-- 
András Péteri

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