org.apache.nutch.scoring.opic

Class OPICScoringFilter

java.lang.Object

org.apache.nutch.scoring.opic.OPICScoringFilter

All Implemented Interfaces:

Configurable, FieldPluggable, Pluggable, ScoringFilter

public class OPICScoringFilter
extends Object
implements ScoringFilter

This plugin implements a variant of an Online Page Importance Computation (OPIC) score, described in this paper: Abiteboul, Serge and Preda, Mihai and Cobena, Gregory (2003), Adaptive On-Line Page Importance Computation .

Author:

Andrzej Bialecki

Field Summary

Fields inherited from interface org.apache.nutch.scoring.ScoringFilter

X_POINT_ID

Constructor Summary

Constructors

Constructor and Description
OPICScoringFilter()

Method Summary

Methods

Modifier and Type	Method and Description
void	distributeScoreToOutlinks(String fromUrl, WebPage row, Collection<ScoreDatum> scoreData, int allCount) Get cash on hand, divide it by the number of outlinks and apply.
float	generatorSortValue(String url, WebPage row, float initSort) Use WebPage.getScore().
Configuration	getConf()
Collection<WebPage.Field>	getFields()
float	indexerScore(String url, NutchDocument doc, WebPage row, float initScore) Dampen the boost value by scorePower.
void	initialScore(String url, WebPage row) Set to 0.0f (unknown value) - inlink contributions will bring it to a correct level.
void	injectedScore(String url, WebPage row) Set an initial score for newly injected pages.
void	setConf(Configuration conf)
void	updateScore(String url, WebPage row, List<ScoreDatum> inlinkedScoreData) Increase the score by a sum of inlinked scores.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OPICScoringFilter

public OPICScoringFilter()

Method Detail

getConf

public Configuration getConf()

Specified by:

getConf in interface Configurable

setConf

public void setConf(Configuration conf)

Specified by:

setConf in interface Configurable

injectedScore

public void injectedScore(String url,
                 WebPage row)
                   throws ScoringFilterException

Description copied from interface: ScoringFilter

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.

Specified by:

injectedScore in interface ScoringFilter

Parameters:

url - url of the page

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

Throws:

ScoringFilterException

initialScore

public void initialScore(String url,
                WebPage row)
                  throws ScoringFilterException

Set to 0.0f (unknown value) - inlink contributions will bring it to a correct level. Newly discovered pages have at least one inlink.

Specified by:

initialScore in interface ScoringFilter

Parameters:

url - url of the page

Throws:

ScoringFilterException

generatorSortValue

public float generatorSortValue(String url,
                       WebPage row,
                       float initSort)
                         throws ScoringFilterException

Use WebPage.getScore().

Specified by:

generatorSortValue in interface ScoringFilter

Parameters:

url - url of the page

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

Throws:

ScoringFilterException

updateScore

public void updateScore(String url,
               WebPage row,
               List<ScoreDatum> inlinkedScoreData)

Increase the score by a sum of inlinked scores.

Specified by:

updateScore in interface ScoringFilter

Parameters:

url - url of the page

distributeScoreToOutlinks

public void distributeScoreToOutlinks(String fromUrl,
                             WebPage row,
                             Collection<ScoreDatum> scoreData,
                             int allCount)

Get cash on hand, divide it by the number of outlinks and apply.

Specified by:

distributeScoreToOutlinks in interface ScoringFilter

Parameters:

fromUrl - url of the source page

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

indexerScore

public float indexerScore(String url,
                 NutchDocument doc,
                 WebPage row,
                 float initScore)

Dampen the boost value by scorePower.

Specified by:

indexerScore in interface ScoringFilter

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.

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.

getFields

public Collection<WebPage.Field> getFields()

Specified by:

getFields in interface FieldPluggable