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RankSys module, providing interfaces and common components for defining metrics.
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/*
* Copyright (C) 2015 Information Retrieval Group at Universidad Autónoma
* de Madrid, http://ir.ii.uam.es
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
package es.uam.eps.ir.ranksys.metrics.rel;
import es.uam.eps.ir.ranksys.core.model.UserModel;
import java.util.stream.Stream;
/**
* Relevance model: deciding when an item is relevant to a user and the
* gain obtained for being recommended.
*
* @author Saúl Vargas ([email protected])
* @author Pablo Castells ([email protected])
*
* @param type of the users
* @param type of the items
*/
public abstract class RelevanceModel extends UserModel {
/**
* Full constructor: allows to specify whether to cache the user
* relevance models and for which users.
*
* @param caching are the user relevance models cached?
* @param users users whose relevance models are cached
*/
public RelevanceModel(boolean caching, Stream users) {
super(caching, users);
}
/**
* No caching constructor.
*/
public RelevanceModel() {
super();
}
/**
* Caching constructor.
*
* @param users users whose relevance models are cached
*/
public RelevanceModel(Stream users) {
super(users);
}
@Override
protected abstract UserRelevanceModel get(U user);
@SuppressWarnings("unchecked")
@Override
public UserRelevanceModel getModel(U user) {
return (UserRelevanceModel) super.getModel(user);
}
/**
* User-specific relevance models.
*
* @param type of the users
* @param type of the items
*/
public interface UserRelevanceModel extends Model {
/**
* Determines whether an item is relevant to the user or not
*
* @param item item to be judged as relevant
* @return true if the item is relevant, false otherwise
*/
public boolean isRelevant(I item);
/**
* Gain obtained by recommending the item. Should be typically
* positive if the item is relevant, and 0 otherwise.
*
* @param item item whose gain is calculated
* @return numerical gain
*/
public double gain(I item);
}
}