package Plucene::Search::Filter;
=head1 NAME
Plucene::Search::Filter - A search filter base class
=head1 DESCRIPTION
This doesn't seem to be being used just yet. But here is some info
on filters:
Filtering means imposing additional restriction on the hit list to
eliminate hits that otherwise would be included in the search results.
There are two ways to filter hits:
=over 4
=item * Search Query - in this approach, provide your custom filter object
to the when you call the search() method. This filter will be called exactly
once to evaluate every document that resulted in non zero score.
=item * Selective Collection - in this approach you perform the regular
search and when you get back the hit list, collect only those that matches
your filtering criteria. In this approach, your filter is called only for
hits that returned by the search method which may be only a subset of the
non zero matches (useful when evaluating your search filter is expensive).
=back
=cut
use strict;
use warnings;
=head1 METHODS
=head2 bits
This must be defined in a subclass
=cut
sub bits { die "bits must be defined in a subclass" }
1;