GenericItemBasedRecommender extends AbstractRecommender implements ItemBasedRecommender { @Override public float estimatePreference(long userID, long itemID) throws TasteException { PreferenceArray preferencesFromUser = getDataModel().getPreferencesFromUser(userID); Float actualPref = getPreferenceForItem(preferencesFromUser, itemID); if (actualPref != null) { return actualPref; } return doEstimatePreference(userID, preferencesFromUser, itemID); } GenericItemBasedRecommender(DataModel dataModel,
                                     ItemSimilarity similarity,
                                     CandidateItemsStrategy candidateItemsStrategy,
                                     MostSimilarItemsCandidateItemsStrategy mostSimilarItemsCandidateItemsStrategy);  GenericItemBasedRecommender(DataModel dataModel, ItemSimilarity similarity); ItemSimilarity getSimilarity(); @Override List<RecommendedItem> recommend(long userID, int howMany, IDRescorer rescorer, boolean includeKnownItems); @Override float estimatePreference(long userID, long itemID); @Override List<RecommendedItem> mostSimilarItems(long itemID, int howMany); @Override List<RecommendedItem> mostSimilarItems(long itemID, int howMany,
                                                Rescorer<LongPair> rescorer); @Override List<RecommendedItem> mostSimilarItems(long[] itemIDs, int howMany); @Override List<RecommendedItem> mostSimilarItems(long[] itemIDs, int howMany,
                                                Rescorer<LongPair> rescorer); @Override List<RecommendedItem> mostSimilarItems(long[] itemIDs,
                                                int howMany,
                                                boolean excludeItemIfNotSimilarToAll); @Override List<RecommendedItem> mostSimilarItems(long[] itemIDs, int howMany,
                                                Rescorer<LongPair> rescorer,
                                                boolean excludeItemIfNotSimilarToAll); @Override List<RecommendedItem> recommendedBecause(long userID, long itemID, int howMany); @Override void refresh(Collection<Refreshable> alreadyRefreshed); @Override String toString();  }
@Test public void testEstimatePref() throws Exception { Recommender recommender = buildRecommender(); assertEquals(0.1f, recommender.estimatePreference(1, 2), EPSILON); }