org.apache.nutch.scoring
Interface ScoringFilter

All Superinterfaces:

Configurable, FieldPluggable, Pluggable

All Known Implementing Classes:

LinkAnalysisScoringFilter, OPICScoringFilter, ScoringFilters, TLDScoringFilter

public interface ScoringFilter
extends Configurable, FieldPluggable

A contract defining behavior of scoring plugins. A scoring filter will manipulate scoring variables in CrawlDatum and in resulting search indexes. Filters can be chained in a specific order, to provide multi-stage scoring adjustments.

Author:

Andrzej Bialecki

Field Summary

static String

X_POINT_ID The name of the extension point.

Method Summary

void	distributeScoreToOutlinks(String fromUrl, WebPage page, Collection<ScoreDatum> scoreData, int allCount) Distribute score value from the current page to all its outlinked pages.
float	generatorSortValue(String url, WebPage page, float initSort) This method prepares a sort value for the purpose of sorting and selecting top N scoring pages during fetchlist generation.
float	indexerScore(String url, NutchDocument doc, WebPage page, float initScore) This method calculates a Lucene document boost.
void	initialScore(String url, WebPage page) Set an initial score for newly discovered pages.
void	injectedScore(String url, WebPage page) Set an initial score for newly injected pages.
void	updateScore(String url, WebPage page, List<ScoreDatum> inlinkedScoreData) This method calculates a new score during table update, based on the values contributed by inlinked pages.

Methods inherited from interface org.apache.hadoop.conf.Configurable

getConf, setConf

Methods inherited from interface org.apache.nutch.plugin.FieldPluggable

getFields

Field Detail

X_POINT_ID

static final String X_POINT_ID

The name of the extension point.

Method Detail

injectedScore

void injectedScore(String url,
                   WebPage page)
                   throws ScoringFilterException

Set an initial score for newly injected pages. Note: newly injected pages may have no inlinks, so filter implementations may wish to set this score to a non-zero value, to give newly injected pages some initial credit.

Parameters:

url - url of the page

page - new page. Filters will modify it in-place.

Throws:

ScoringFilterException

initialScore

void initialScore(String url,
                  WebPage page)
                  throws ScoringFilterException

Set an initial score for newly discovered pages. Note: newly discovered pages have at least one inlink with its score contribution, so filter implementations may choose to set initial score to zero (unknown value), and then the inlink score contribution will set the "real" value of the new page.

Parameters:

url - url of the page

page -

Throws:

ScoringFilterException

generatorSortValue

float generatorSortValue(String url,
                         WebPage page,
                         float initSort)
                         throws ScoringFilterException

This method prepares a sort value for the purpose of sorting and selecting top N scoring pages during fetchlist generation.

Parameters:

url - url of the page

datum - page row. Modifications will be persisted.

initSort - initial sort value, or a value from previous filters in chain

Throws:

ScoringFilterException

distributeScoreToOutlinks

void distributeScoreToOutlinks(String fromUrl,
                               WebPage page,
                               Collection<ScoreDatum> scoreData,
                               int allCount)
                               throws ScoringFilterException

Distribute score value from the current page to all its outlinked pages.

Parameters:

fromUrl - url of the source page

row - page row

scoreData - A list of OutlinkedScoreDatums for every outlink. These OutlinkedScoreDatums will be passed to #updateScore(String, OldWebTableRow, List) for every outlinked URL.

allCount - number of all collected outlinks from the source page

Throws:

ScoringFilterException

updateScore

void updateScore(String url,
                 WebPage page,
                 List<ScoreDatum> inlinkedScoreData)
                 throws ScoringFilterException

This method calculates a new score during table update, based on the values contributed by inlinked pages.

Parameters:

url - url of the page

page -

inlinked - list of OutlinkedScoreDatums for all inlinks pointing to this URL.

Throws:

ScoringFilterException

indexerScore

float indexerScore(String url,
                   NutchDocument doc,
                   WebPage page,
                   float initScore)
                   throws ScoringFilterException

This method calculates a Lucene document boost.

Parameters:

url - url of the page

doc - document. NOTE: this already contains all information collected by indexing filters. Implementations may modify this instance, in order to store/remove some information.

row - page row

initScore - initial boost value for the Lucene document.

Returns:

boost value for the Lucene document. This value is passed as an argument to the next scoring filter in chain. NOTE: implementations may also express other scoring strategies by modifying Lucene document directly.

Throws:

ScoringFilterException