org.apache.mahout.cf.taste.impl.recommender

Class NullRescorer<T>

java.lang.Object

org.apache.mahout.cf.taste.impl.recommender.NullRescorer<T>

All Implemented Interfaces:

IDRescorer, Rescorer<T>

public final class NullRescorer<T>
extends Object
implements Rescorer<T>, IDRescorer

A simple Rescorer which always returns the original score.

Method Summary

Modifier and Type	Method and Description
static IDRescorer	getItemInstance()
static Rescorer<LongPair>	getItemItemPairInstance()
static IDRescorer	getUserInstance()
static Rescorer<LongPair>	getUserUserPairInstance()
boolean	isFiltered(long id) Returns true to exclude the given thing.
boolean	isFiltered(T thing) Returns true to exclude the given thing.
double	rescore(long id, double originalScore)
double	rescore(T thing, double originalScore)
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

getItemInstance

public static IDRescorer getItemInstance()

getUserInstance

public static IDRescorer getUserInstance()

getItemItemPairInstance

public static Rescorer<LongPair> getItemItemPairInstance()

getUserUserPairInstance

public static Rescorer<LongPair> getUserUserPairInstance()

rescore

public double rescore(T thing,
                      double originalScore)

Specified by:

rescore in interface Rescorer<T>

Parameters:

thing - to rescore

originalScore - current score for item

Returns:

same originalScore as new score, always

isFiltered

public boolean isFiltered(T thing)

Description copied from interface: Rescorer

Returns true to exclude the given thing.

Specified by:

isFiltered in interface Rescorer<T>

Parameters:

thing - the thing to filter

Returns:

true to exclude, false otherwise

rescore

public double rescore(long id,
                      double originalScore)

Specified by:

rescore in interface IDRescorer

Parameters:

id - ID of thing (user, item, etc.) to rescore

originalScore - original score

Returns:

modified score, or Double.NaN to indicate that this should be excluded entirely

isFiltered

public boolean isFiltered(long id)

Description copied from interface: IDRescorer

Returns true to exclude the given thing.

Specified by:

isFiltered in interface IDRescorer

Parameters:

id - ID of thing (user, item, etc.) to rescore

Returns:

true to exclude, false otherwise

toString

public String toString()

Overrides:

toString in class Object