org.terrier.querying

Interface PostFilter

All Known Implementing Classes:

Decorate, Scope, SimpleDecorate, SiteFilter

public interface PostFilter

PostFilters are designed to complement PostProcesses. While PostProcesses operate on the entire resultset at once, with PostFilters, each PostFilter is called for each result in the resultset. According to the return of filter() the result can then be included, discarded, or (un)boosted in the resultset. Possible return values for filter are FILTER_OK, FILTER_REMOVE, FILTER_ADJUSTED Which PostFilters are run, and when is controlled by two properties, as mentioned below.
Properties

• querying.postfilters.controls : A comma separated list of control to PostFilter class mappings. Mappings are separated by ":". eg querying.postfilters.controls=scope:Scope
• querying.postfilters.order : The order postfilters should be run in

'''NB:''' Initialisation and running of post filters is carried out by the Manager.

Author:

Craig Macdonald

Field Summary

Fields

Modifier and Type	Field and Description
static byte	FILTER_ADJUSTED The score for this result has been adjusted, please ensure the resultset is re-sorted
static byte	FILTER_OK This result should be included in the resultset
static byte	FILTER_REMOVE This result should not be included in the resultset

Method Summary

Methods

Modifier and Type	Method and Description
byte	filter(Manager m, SearchRequest srq, ResultSet results, int DocAtNumber, int docid) Called for each result in the resultset, used to filter out unwanted results.
void	new_query(Manager m, SearchRequest srq, ResultSet rs) Called before the processing of a resultset using this PostFilter is applied.

Field Detail

FILTER_OK

static final byte FILTER_OK

This result should be included in the resultset

See Also:

Constant Field Values

FILTER_REMOVE

static final byte FILTER_REMOVE

This result should not be included in the resultset

See Also:

Constant Field Values

FILTER_ADJUSTED

static final byte FILTER_ADJUSTED

The score for this result has been adjusted, please ensure the resultset is re-sorted

See Also:

Constant Field Values

Method Detail

new_query

void new_query(Manager m,
             SearchRequest srq,
             ResultSet rs)

Called before the processing of a resultset using this PostFilter is applied. Can be used to save information for the duration of the query.

Parameters:

m - The manager controlling this query

srq - The search request being processed

rs - the resultset that is being iterated through

filter

byte filter(Manager m,
          SearchRequest srq,
          ResultSet results,
          int DocAtNumber,
          int docid)

Called for each result in the resultset, used to filter out unwanted results.

Parameters:

m - The manager controlling this query

srq - The search request being processed

DocAtNumber - which array index (rank) in the resultset have we reached

docid - The docid of the currently being procesed result.