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

java.lang.Object
  extended by 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
protected AbstractItemSimilarity(DataModel dataModel)
           
 
Method Summary
 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 Refreshable.refresh(Collection) method on some object. This ensure that objects in a refresh dependency graph aren't refreshed twice needlessly.


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