Class: Ferret::Search::QueryFilter

Summary

QueryFilter can be used to restrict one queries results by another queries results, basically "and"ing them together. Of course you could easily use a BooleanQuery to do this. The reason you may choose to use a QueryFilter is that Filter results are cached so if you have one query that is often added to other queries you may want to use a QueryFilter for performance reasons.

Example

Let‘s say you have a field +:approved+ which you set to yes when a document is approved for display. You‘ll probably want to add a Filter which filters approved documents to display to your users. This is the perfect use case for a QueryFilter. 

  filter = QueryFilter.new(TermQuery.new(:approved, "yes"))

Just remember to use the same QueryFilter each time to take advantage of caching. Don‘t create a new one for each request. Of course, this won‘t work in a CGI application.

Public Class Methods

QueryFilter.new(query) → filter

Create a new QueryFilter which applies the query query. 

/*
 *  call-seq:
 *     QueryFilter.new(query) -> filter
 *
 *  Create a new QueryFilter which applies the query +query+.
 */
static VALUE
frt_qf_init(VALUE self, VALUE rquery)
{
    Query *q;
    Filter *f;
    Data_Get_Struct(rquery, Query, q);
    f = qfilt_new(q);
    Frt_Wrap_Struct(self, NULL, &frt_f_free, f);
    object_add(f, self);
    return self;
}