org.grouplens.lenskit.eval.traintest

Class SharedPreferenceSnapshot

java.lang.Object

org.grouplens.lenskit.eval.traintest.SharedPreferenceSnapshot

All Implemented Interfaces:

Closeable, Serializable, AutoCloseable, PreferenceSnapshot

@Shareable
public class SharedPreferenceSnapshot
extends Object
implements PreferenceSnapshot, Serializable

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SharedPreferenceSnapshot(PreferenceSnapshot snapshot)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the build context.
LongCollection	getItemIds() Get the set of item IDs in the snapshot.
FastCollection<IndexedPreference>	getRatings() Get the collection of ratings in the snapshot.
LongCollection	getUserIds() Get the set of user IDs in the snapshot.
FastCollection<IndexedPreference>	getUserRatings(long userId) Get the ratings for a particular user.
Index	itemIndex() Get the item ID index.
static Supplier<SharedPreferenceSnapshot>	supplier(TTDataSet data) Construct a supplier of a snapshot of the training data from a data set.
Index	userIndex() Get the user ID index.
SparseVector	userRatingVector(long userId) Get the current preferences of a particular user in SparseVector form.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SharedPreferenceSnapshot

public SharedPreferenceSnapshot(PreferenceSnapshot snapshot)

Method Detail

getUserIds

public LongCollection getUserIds()

Description copied from interface: PreferenceSnapshot

Get the set of user IDs in the snapshot.

Specified by:

getUserIds in interface PreferenceSnapshot

Returns:

A set of all known user IDs.

getItemIds

public LongCollection getItemIds()

Description copied from interface: PreferenceSnapshot

Get the set of item IDs in the snapshot.

Specified by:

getItemIds in interface PreferenceSnapshot

Returns:

A set of all known item IDs.

userIndex

public Index userIndex()

Description copied from interface: PreferenceSnapshot

Get the user ID index.

Specified by:

userIndex in interface PreferenceSnapshot

Returns:

The index mapping between user IDs and user indices.

itemIndex

public Index itemIndex()

Description copied from interface: PreferenceSnapshot

Get the item ID index.

Specified by:

itemIndex in interface PreferenceSnapshot

Returns:

The index mapping between user IDs and user indices.

getRatings

public FastCollection<IndexedPreference> getRatings()

Description copied from interface: PreferenceSnapshot

Get the collection of ratings in the snapshot. The ratings are returned in an undetermined order. It is guaranteed that no duplicate ratings appear - each (user,item) pair is rated at most once. Each preference's index is also in the range [0,len), where len is the size of this collection.

Modifying the returned indexed preferences will not modify the underlying snapshot.

Specified by:

getRatings in interface PreferenceSnapshot

Returns:

All ratings in the system.

getUserRatings

public FastCollection<IndexedPreference> getUserRatings(long userId)

Description copied from interface: PreferenceSnapshot

Get the ratings for a particular user. It is guaranteed that no duplicate ratings appear - each (user,item) pair is rated at most once.

Modifying the returned indexed preferences will not modify the underlying snapshot.

Specified by:

getUserRatings in interface PreferenceSnapshot

Parameters:

userId - The user's ID.

Returns:

The user's ratings, or an empty collection if the user is unknown.

close

public void close()

Description copied from interface: PreferenceSnapshot

Close the build context. This overrides Closeable.close() to drop the exception that can be thrown.

After the build context has been closed, all methods are allowed to fail. Objects returned from those methods, however, should continue to be valid.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface PreferenceSnapshot

userRatingVector

public SparseVector userRatingVector(long userId)

Description copied from interface: PreferenceSnapshot

Get the current preferences of a particular user in SparseVector form.

Specified by:

userRatingVector in interface PreferenceSnapshot

Parameters:

userId - The user's ID.

Returns:

The user's rating vector.

supplier

public static Supplier<SharedPreferenceSnapshot> supplier(TTDataSet data)

Construct a supplier of a snapshot of the training data from a data set. The snapshot is cached in a soft reference, so will be released when unused for a time.

Parameters:

data - The data set.

Returns:

A supplier that provides access to a shared preference snapshot.