@Test
public void testRecommender() throws Exception {
MutableInt recommendCount = new MutableInt();
Recommender mockRecommender = new MockRecommender(recommendCount);
Recommender cachingRecommender = new CachingRecommender(mockRecommender);
cachingRecommender.recommend(1, 1);
assertEquals(1, recommendCount.intValue());
cachingRecommender.recommend(2, 1);
assertEquals(2, recommendCount.intValue());
cachingRecommender.recommend(1, 1);
assertEquals(2, recommendCount.intValue());
cachingRecommender.recommend(2, 1);
assertEquals(2, recommendCount.intValue());
cachingRecommender.refresh(null);
cachingRecommender.recommend(1, 1);
assertEquals(3, recommendCount.intValue());
cachingRecommender.recommend(2, 1);
assertEquals(4, recommendCount.intValue());
cachingRecommender.recommend(3, 1);
assertEquals(5, recommendCount.intValue());
// Results from this recommend() method can be cached...
IDRescorer rescorer = NullRescorer.getItemInstance();
cachingRecommender.refresh(null);
cachingRecommender.recommend(1, 1, rescorer);
assertEquals(6, recommendCount.intValue());
cachingRecommender.recommend(2, 1, rescorer);
assertEquals(7, recommendCount.intValue());
cachingRecommender.recommend(1, 1, rescorer);
assertEquals(7, recommendCount.intValue());
cachingRecommender.recommend(2, 1, rescorer);
assertEquals(7, recommendCount.intValue());
// until you switch Rescorers
cachingRecommender.recommend(1, 1, null);
assertEquals(8, recommendCount.intValue());
cachingRecommender.recommend(2, 1, null);
assertEquals(9, recommendCount.intValue());
cachingRecommender.refresh(null);
cachingRecommender.estimatePreference(1, 1);
assertEquals(10, recommendCount.intValue());
cachingRecommender.estimatePreference(1, 2);
assertEquals(11, recommendCount.intValue());
cachingRecommender.estimatePreference(1, 2);
assertEquals(11, recommendCount.intValue());
}
@Override
public Void call() throws TasteException {
for (Preference realPref : prefs) {
float estimatedPreference = Float.NaN;
try {
estimatedPreference = recommender.estimatePreference(testUserID, realPref.getItemID());
} catch (NoSuchUserException nsue) {
// It's possible that an item exists in the test data but
// not training data in which case
// NSEE will be thrown. Just ignore it and move on.
log.info("User exists in test data but not training data: {}", testUserID);
} catch (NoSuchItemException nsie) {
log.info("Item exists in test data but not training data: {}", realPref.getItemID());
}
if (Float.isNaN(estimatedPreference)) {
noEstimateCounter.incrementAndGet();
} else {
estimatedPreference = capEstimatedPreference(estimatedPreference);
processOneEstimate(estimatedPreference, realPref);
}
}
return null;
}
