AbstractRecommenderRunner.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.rec.runner;

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

import java.util.List;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.logging.Logger;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * Generic recommender runner. This class handles the print of the output.
 *
 * @author Saúl Vargas (saul.vargas@uam.es)
 *
 * @param <U> type of the users
 * @param <I> type of the items
 */
public abstract class AbstractRecommenderRunner<U, I> implements RecommenderRunner<U, I> {

    private static final Logger LOG = Logger.getLogger(AbstractRecommenderRunner.class.getName());

    private final List<U> users;

    /**
     * Constructor.
     *
     * @param users target users for which recommendations are generated
     */
    public AbstractRecommenderRunner(Stream<U> users) {
        this.users = users.sorted().collect(Collectors.toList());
    }

    /**
     * Prints the recommendations.
     *
     * @param recProvider function that provides the recommendations by calling a recommender
     * @param consumer recommendation consumer
     */
    protected void run(Function<U, Recommendation<U, I>> recProvider, Consumer<Recommendation<U, I>> consumer) {
        users.parallelStream().forEach(user -> consumer.accept(recProvider.apply(user)));
    }
}