Cedric,

The algorithms of the four scorers used by BooleanScorer2 are
fairly straightforward by themselves, a short look at the code
should  suffice to get the idea.
The exception to that is BooleanScorer, but since this is
only used as an option, it's not really necessary to explain it.
The one advantage of BooleanScorer is that it is very fast for
disjunctions.

Regards,
Paul Elschot



On Sunday 23 September 2007 13:11, melix wrote:
> 
> Hi Paul,
> 
> His there any document which explains how those scorers interact ? My main
> problem is finding out how to create a match instance for each call to
> next(), and in boolean queries, it is rather difficult to figure out how to
> do that. An explanation on the algorithms would surely help.
> 
> Thx.
> 
> 
> Paul Elschot wrote:
> > 
> > Cedric,
> > 
> > On Saturday 22 September 2007 11:45, melix wrote:
> >> The problem was even harder when I had to add the match() method to the
> >> BooleanQuery : this class is so complex, and uses so many protected or
> >> inner
> >> classes (for optimization purposes, I must understand) that I would have
> >> to
> >> copy a lot of the original source code just to add my method. As
> >> documentation on how it works is really hard to find, I decided it would
> >> be
> >> simpler if I wrote my own boolean queries (which is what I've done now).
> >> I
> >> know it must be much less performant, but makes the tasks much easier.
> > 
> > As long as your scorers are (a combination of) normal target classes of 
> > BooleanScorer2 you should get the same efficiency.
> > These target classes are ConjunctionScorer, DisjunctionSumScorer, 
> > ReqOptSumScorer and ReqExclScorer. These scorees can be used for
> > "boolean" operators AND, OR, ANDoptional, and ANDNOT.
> > For some cases of top level OR, BooleanScorer can also be a target
> > scorer when scoring out of document order is allowed.
> > Most of the complexity of BooleanScorer2 comes from mapping
> > the + and - query operators for required and prohibited subqueries
> > to these target scorers.
> > 
> > Regards,
> > Paul Elschot
> > 
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