@Test
public void testSnapshot() throws RecommenderBuildException {
List<Rating> rs = new ArrayList<Rating>();
rs.add(Ratings.make(1, 5, 2));
rs.add(Ratings.make(1, 7, 4));
rs.add(Ratings.make(8, 4, 5));
rs.add(Ratings.make(8, 5, 4));
EventDAO dao = EventCollectionDAO.create(rs);
LenskitConfiguration config = new LenskitConfiguration();
config.bind(EventDAO.class).to(dao);
config.bind(ItemScorer.class).to(UserUserItemScorer.class);
config.bind(NeighborFinder.class).to(SnapshotNeighborFinder.class);
LenskitRecommenderEngine engine = LenskitRecommenderEngine.build(config);
Recommender rec = engine.createRecommender();
assertThat(rec.getItemScorer(), instanceOf(UserUserItemScorer.class));
assertThat(rec.getItemRecommender(), instanceOf(TopNItemRecommender.class));
RatingPredictor pred = rec.getRatingPredictor();
assertThat(pred, instanceOf(SimpleRatingPredictor.class));
Recommender rec2 = engine.createRecommender();
assertThat(rec2.getItemScorer(), not(sameInstance(rec.getItemScorer())));
}
@SuppressWarnings("deprecation")
@Test
public void testUserUserRecommenderEngineCreate() {
Recommender rec = engine.createRecommender();
assertThat(rec.getItemScorer(), instanceOf(UserUserItemScorer.class));
assertThat(rec.getItemRecommender(), instanceOf(TopNItemRecommender.class));
RatingPredictor pred = rec.getRatingPredictor();
assertThat(pred, instanceOf(SimpleRatingPredictor.class));
assertThat(((SimpleRatingPredictor) pred).getScorer(), sameInstance(rec.getItemScorer()));
}
public static void main(String[] args) throws RecommenderBuildException {
LenskitConfiguration config = configureRecommender();
logger.info("building recommender");
Recommender rec = LenskitRecommender.build(config);
if (args.length == 0) {
logger.error("No users specified; provide user IDs as command line arguments");
}
// we automatically get a useful recommender since we have a scorer
ItemRecommender irec = rec.getItemRecommender();
assert irec != null;
try {
// Generate 5 recommendations for each user
for (String user : args) {
long uid;
try {
uid = Long.parseLong(user);
} catch (NumberFormatException e) {
logger.error("cannot parse user {}", user);
continue;
}
logger.info("searching for recommendations for user {}", user);
List<ScoredId> recs = irec.recommend(uid, 5);
if (recs.isEmpty()) {
logger.warn("no recommendations for user {}, do they exist?", uid);
}
System.out.format("recommendations for user %d:\n", uid);
for (ScoredId id : recs) {
System.out.format(" %d: %.4f\n", id.getId(), id.getScore());
}
}
} catch (UnsupportedOperationException e) {
if (e.getMessage().equals("stub implementation")) {
System.out.println("Congratulations, the stub builds and runs!");
}
}
}