Recommendability.java

/* 
 * 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.basic;

import es.uam.eps.ir.ranksys.metrics.AbstractRecommendationMetric;
import es.uam.eps.ir.ranksys.core.Recommendation;

/**
 * Recommendability: binary metric that determines whether the user receives
 * a non-empty recommendation or not.
 *
 * @author Saúl Vargas (saul.vargas@uam.es)
 * 
 * @param <U> type of the users
 * @param <I> type of the items
 */
public class Recommendability<U, I> extends AbstractRecommendationMetric<U, I> {

    /**
     * Returns a score for the recommendation list.
     *
     * @param recommendation recommendation list
     * @return score of the metric to the recommendation
     */
    @Override
    public double evaluate(Recommendation<U, I> recommendation) {
        return recommendation.getItems().isEmpty() ? 0.0 : 1.0;
    }
}