public IList <RecommendedItem> RecommendedBecause(Object userID, Object itemID, int howMany)
{
if (userID == null)
{
throw new ArgumentNullException("userID is null");
}
if (itemID == null)
{
throw new ArgumentNullException("itemID is null");
}
if (howMany < 1)
{
throw new ArgumentException("howMany must be at least 1");
}
DataModel model = this.DataModel;
User user = model.GetUser(userID);
Item recommendedItem = model.GetItem(itemID);
TopItems.Estimator <Item> estimator = new RecommendedBecauseEstimator(user, recommendedItem, correlation);
ICollection <Item> allUserItems = new HashedSet <Item>();
Preference[] prefs = user.GetPreferencesAsArray();
foreach (Preference pref in prefs)
{
allUserItems.Add(pref.Item);
}
allUserItems.Remove(recommendedItem);
return(TopItems.GetTopItems(howMany, allUserItems, NullRescorer <Item> .Instance, estimator));
}
public List <RecommendedItem> recommendedBecause(long userID, long itemID, int howMany)
{
DataModel model = this.getDataModel();
TopItems.Estimator <long> estimator = new RecommendedBecauseEstimator(this, userID, itemID);
PreferenceArray array = model.getPreferencesFromUser(userID);
int size = array.length();
FastIDSet set = new FastIDSet(size);
for (int i = 0; i < size; i++)
{
set.add(array.getItemID(i));
}
set.remove(itemID);
return(TopItems.getTopItems(howMany, set.GetEnumerator(), null, estimator));
}
public List <IRecommendedItem> RecommendedBecause(long userID, long itemID, int howMany)
{
//Preconditions.checkArgument(howMany >= 1, "howMany must be at least 1");
IDataModel model = GetDataModel();
TopItems.IEstimator <long> estimator = new RecommendedBecauseEstimator(this, userID, itemID);
IPreferenceArray prefs = model.GetPreferencesFromUser(userID);
int size = prefs.Length();
FastIDSet allUserItems = new FastIDSet(size);
for (int i = 0; i < size; i++)
{
allUserItems.Add(prefs.GetItemID(i));
}
allUserItems.Remove(itemID);
return(TopItems.GetTopItems(howMany, allUserItems.GetEnumerator(), null, estimator));
}
