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

java.lang.Object
  extended by 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
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


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