NAME¶
LucyX::Search::Filter - Build a caching filter based on results of a Query.
SYNOPSIS¶
my %category_filters;
for my $category (qw( sweet sour salty bitter )) {
my $cat_query = Lucy::Search::TermQuery->new(
field => 'category',
term => $category,
);
$category_filters{$category} = LucyX::Search::Filter->new(
query => $cat_query,
);
}
while ( my $cgi = CGI::Fast->new ) {
my $user_query = $cgi->param('q');
my $filter = $category_filters{ $cgi->param('category') };
my $and_query = Lucy::Search::ANDQuery->new;
$and_query->add_child($user_query);
$and_query->add_child($filter);
my $hits = $searcher->hits( query => $and_query );
...
DESCRIPTION¶
A Filter is a Lucy::Search::Query subclass that can be used to filter the
results of another Query. The effect is very similar to simply using the
wrapped inner query, but there are two important differences:
- •
- A Filter does not contribute to the score of the documents it
matches.
- •
- A Filter caches its results, so it is more efficient if you use it more
than once.
To obtain logically equivalent results to the Filter but avoid the caching,
substitute the wrapped query but use
set_boost() to set its
"boost" to 0.
METHODS¶
new¶
my $filter = LucyX::Search::Filter->new(
query => $query;
);
Constructor. Takes one hash-style parameter, "query", which must be an
object belonging to a subclass of Lucy::Search::Query.
BUGS¶
Filters do not cache when used in a search cluster with LucyX::Remote's
SearchServer and SearchClient.