org.apache.mahout.cf.taste.impl.similarity

Class AbstractItemSimilarity

java.lang.Object

org.apache.mahout.cf.taste.impl.similarity.AbstractItemSimilarity

All Implemented Interfaces:

Refreshable, ItemSimilarity

Direct Known Subclasses:

CityBlockSimilarity, EuclideanDistanceSimilarity, LogLikelihoodSimilarity, PearsonCorrelationSimilarity, TanimotoCoefficientSimilarity, UncenteredCosineSimilarity

public abstract class AbstractItemSimilarity
extends Object
implements ItemSimilarity

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractItemSimilarity(DataModel dataModel)

Method Summary

Modifier and Type	Method and Description
long[]	allSimilarItemIDs(long itemID)
protected DataModel	getDataModel()
void	refresh(Collection<Refreshable> alreadyRefreshed) Triggers "refresh" -- whatever that means -- of the implementation.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.mahout.cf.taste.similarity.ItemSimilarity

itemSimilarities, itemSimilarity

Constructor Detail

AbstractItemSimilarity

protected AbstractItemSimilarity(DataModel dataModel)

Method Detail

getDataModel

protected DataModel getDataModel()

allSimilarItemIDs

public long[] allSimilarItemIDs(long itemID)
                         throws TasteException

Specified by:

allSimilarItemIDs in interface ItemSimilarity

Returns:

all IDs of similar items, in no particular order

Throws:

TasteException

refresh

public void refresh(Collection<Refreshable> alreadyRefreshed)

Description copied from interface: Refreshable

Triggers "refresh" -- whatever that means -- of the implementation. The general contract is that any Refreshable should always leave itself in a consistent, operational state, and that the refresh atomically updates internal state from old to new.

Specified by:

refresh in interface Refreshable

Parameters:

alreadyRefreshed - Refreshables that are known to have already been refreshed as a result of an initial call to a {#refresh(Collection)} method on some object. This ensure that objects in a refresh dependency graph aren't refreshed twice needlessly.