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From Paul Elschot <paul.elsc...@xs4all.nl>
Subject Re: MultiSegmentQueryFilter enhancement for interactive indexes?
Date Sat, 08 Jul 2006 07:24:42 GMT
On Saturday 08 July 2006 05:44, robert engels wrote:
> Agreed. The interface I proposed supports both sequential and random  
> access to the filter - hiding the implementation.

For query searching, random access to a Filter is only needed
in the forward direction, e.g. by nextInclude(docNr) or skipTo(docNr).

As for why it's so involved:

Making a "rewritten" Filter work more like a Scorer has the advantage
that combinations of filters can (also) be evaluated using the same
mechanisms as currently existing for Scorers. For this, some additions
to the existing code will be needed, like adding an
add(Filter, BooleanClause.Occur) to BooleanQuery, and a similar
addition of a Matcher (proposed superclass of Scorer to "rewrite" a
Filter to) to some of the underlying scorers.
Such occurrences of filters are only "must" and "must not", "should"
doesn't make sense because there is no score value.

Also, it makes sense to have an explain() method for a "rewritten"
Filter, because it can be for searching a query.

Regards,
Paul Elschot

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