es.uam.eps.ir.ranksys.rec.fast

Class AbstractFastRecommender<U,I>

java.lang.Object

es.uam.eps.ir.ranksys.rec.AbstractRecommender<U,I>

es.uam.eps.ir.ranksys.rec.fast.AbstractFastRecommender<U,I>

Type Parameters:

U - type of the users

I - type of the items

All Implemented Interfaces:

ItemIndex<I>, UserIndex<U>, FastItemIndex<I>, FastUserIndex<U>, FastRecommender<U,I>, Recommender<U,I>

Direct Known Subclasses:

FastRankingRecommender, FMRecommender, LDARecommender, MFRecommender, PopularityRecommender, RandomRecommender, RerankingRecommender

public abstract class AbstractFastRecommender<U,I>
extends AbstractRecommender<U,I>
implements FastRecommender<U,I>

Abstract (fast) recommender. It implements the free and candidate-based recommendation methods as variants of the filter recommendation.

Author:

Saúl Vargas (saul.vargas@uam.es)

Field Summary

Fields

Modifier and Type	Field and Description
protected FastItemIndex<I>	iIndex Fast item index.
protected FastUserIndex<U>	uIndex Fast user index.

Constructor Summary

Constructors

Constructor and Description
AbstractFastRecommender(FastUserIndex<U> uIndex, FastItemIndex<I> iIndex) Constructor.

Method Summary

Modifier and Type	Method and Description
FastRecommendation	getRecommendation(int uidx) Free recommendation.
FastRecommendation	getRecommendation(int uidx, int maxLength) Free recommendation.
abstract FastRecommendation	getRecommendation(int uidx, int maxLength, IntPredicate filter) Filter recommendation.
FastRecommendation	getRecommendation(int uidx, IntPredicate filter) Filter recommendation.
FastRecommendation	getRecommendation(int uidx, IntStream candidates) Candidates ranking.
Recommendation<U,I>	getRecommendation(U u, int maxLength) Free recommendation.
Recommendation<U,I>	getRecommendation(U u, int maxLength, Predicate<I> filter) Filter recommendation.
Recommendation<U,I>	getRecommendation(U u, Stream<I> candidates) Candidates ranking.
I	iidx2item(int iidx) Returns the item represented with the index.
int	item2iidx(I i) Returns the index assigned to the item.
int	numItems() Counts the number of indexed items.
int	numUsers() Counts the number of indexed users.
U	uidx2user(int uidx) Returns the user represented with the index.
int	user2uidx(U u) Returns the index assigned to the user.

Methods inherited from class es.uam.eps.ir.ranksys.rec.AbstractRecommender

getRecommendation, getRecommendation

Methods inherited from class java.lang.Object

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

Methods inherited from interface es.uam.eps.ir.ranksys.rec.Recommender

getRecommendation, getRecommendation

Methods inherited from interface es.uam.eps.ir.ranksys.fast.index.FastUserIndex

containsUser, getAllUidx, getAllUsers, uidx2user, uidx2user, user2uidx, user2uidx

Methods inherited from interface es.uam.eps.ir.ranksys.fast.index.FastItemIndex

containsItem, getAllIidx, getAllItems, iidx2item, iidx2item, item2iidx, item2iidx

Field Detail

uIndex

protected final FastUserIndex<U> uIndex

Fast user index.

iIndex

protected final FastItemIndex<I> iIndex

Fast item index.

Constructor Detail

AbstractFastRecommender

public AbstractFastRecommender(FastUserIndex<U> uIndex,
                               FastItemIndex<I> iIndex)

Constructor.

Parameters:

uIndex - user index

iIndex - item index

Method Detail

numUsers

public int numUsers()

Description copied from interface: UserIndex

Counts the number of indexed users.

Specified by:

numUsers in interface UserIndex<U>

Returns:

the total number of users

user2uidx

public int user2uidx(U u)

Description copied from interface: FastUserIndex

Returns the index assigned to the user.

Specified by:

user2uidx in interface FastUserIndex<U>

Parameters:

u - user

Returns:

the index of the user, or -1 if the user does not exist

uidx2user

public U uidx2user(int uidx)

Description copied from interface: FastUserIndex

Returns the user represented with the index.

Specified by:

uidx2user in interface FastUserIndex<U>

Parameters:

uidx - user index

Returns:

the user whose index is uidx

numItems

public int numItems()

Description copied from interface: ItemIndex

Counts the number of indexed items.

Specified by:

numItems in interface ItemIndex<I>

Returns:

the total number of item

item2iidx

public int item2iidx(I i)

Description copied from interface: FastItemIndex

Returns the index assigned to the item.

Specified by:

item2iidx in interface FastItemIndex<I>

Parameters:

i - item

Returns:

the index of the item, or -1 if the item does not exist

iidx2item

public I iidx2item(int iidx)

Description copied from interface: FastItemIndex

Returns the item represented with the index.

Specified by:

iidx2item in interface FastItemIndex<I>

Parameters:

iidx - item index

Returns:

the item whose index is iidx

getRecommendation

public Recommendation<U,I> getRecommendation(U u,
                                             int maxLength)

Description copied from interface: Recommender

Free recommendation. Generate recommendations without any restriction on the items being recommended, but with a limit on the list size.

Specified by:

getRecommendation in interface Recommender<U,I>

Overrides:

getRecommendation in class AbstractRecommender<U,I>

Parameters:

u - user to be issued a recommendation

maxLength - maximum length of recommendation

Returns:

a recommendation list

getRecommendation

public FastRecommendation getRecommendation(int uidx)

Description copied from interface: FastRecommender

Free recommendation. Generate recommendations without any restriction on the items being recommended.

Specified by:

getRecommendation in interface FastRecommender<U,I>

Parameters:

uidx - index of the user to be issued a recommendation

Returns:

a (fast) recommendation list

getRecommendation

public FastRecommendation getRecommendation(int uidx,
                                            int maxLength)

Description copied from interface: FastRecommender

Free recommendation. Generate recommendations without any restriction on the items being recommended, but with a limit on the list size.

Specified by:

getRecommendation in interface FastRecommender<U,I>

Parameters:

uidx - index of the user to be issued a recommendation

maxLength - maximum length of recommendation

Returns:

a (fast) recommendation list

getRecommendation

public Recommendation<U,I> getRecommendation(U u,
                                             int maxLength,
                                             Predicate<I> filter)

Description copied from interface: Recommender

Filter recommendation. Recommends only the items that pass the filter up to a maximum list size.

Specified by:

getRecommendation in interface Recommender<U,I>

Specified by:

getRecommendation in class AbstractRecommender<U,I>

Parameters:

u - user to be issued a recommendation

maxLength - maximum length of recommendation

filter - filter to decide which items might be recommended

Returns:

a recommendation list

getRecommendation

public FastRecommendation getRecommendation(int uidx,
                                            IntPredicate filter)

Description copied from interface: FastRecommender

Filter recommendation. Recommends only the items that pass the filter.

Specified by:

getRecommendation in interface FastRecommender<U,I>

Parameters:

uidx - index of the user to be issued a recommendation

filter - (fast) filter to decide which items might be recommended

Returns:

a (fast) recommendation list

getRecommendation

public abstract FastRecommendation getRecommendation(int uidx,
                                                     int maxLength,
                                                     IntPredicate filter)

Description copied from interface: FastRecommender

Filter recommendation. Recommends only the items that pass the filter up to a maximum list size.

Specified by:

getRecommendation in interface FastRecommender<U,I>

Parameters:

uidx - index of the user to be issued a recommendation

maxLength - maximum length of recommendation

filter - (fast) filter to decide which items might be recommended

Returns:

a (fast) recommendation list

getRecommendation

public Recommendation<U,I> getRecommendation(U u,
                                             Stream<I> candidates)

Description copied from interface: Recommender

Candidates ranking. Create a list that may contain only the items in the candidates set.

Specified by:

getRecommendation in interface Recommender<U,I>

Overrides:

getRecommendation in class AbstractRecommender<U,I>

Parameters:

u - user to be issued a recommendation

candidates - candidate items to be included in the recommendation

Returns:

a recommendation list

getRecommendation

public FastRecommendation getRecommendation(int uidx,
                                            IntStream candidates)

Description copied from interface: FastRecommender

Candidates ranking. Create a list that may contain only the items in the candidates set.

Specified by:

getRecommendation in interface FastRecommender<U,I>

Parameters:

uidx - item of the user to be issued a recommendation

candidates - candidate items to be included in the recommendation

Returns:

a recommendation list