org.lenskit.api.ResultMap Maven / Gradle / Ivy
/*
* LensKit, an open source recommender systems toolkit.
* Copyright 2010-2014 LensKit Contributors. See CONTRIBUTORS.md.
* Work on LensKit has been funded by the National Science Foundation under
* grants IIS 05-34939, 08-08692, 08-12148, and 10-17697.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.lenskit.api;
import javax.annotation.Nullable;
import java.util.Map;
/**
* A map of results from a recommender operation. This is returned from operations such as *predict* that provide
* scores or values for a collection of items, but do not rank or find items.
*/
public interface ResultMap extends Map, Iterable {
/**
* View this result set as a map from longs to doubles.
* @return A map view of this result set.
*/
Map scoreMap();
/**
* Get a result without boxing the key.
* @param key The item ID.
* @return The result, or {@code null} if the key is not in the map.
*/
@Nullable
Result get(long key);
/**
* Get the score associated with an ID.
* @param id The ID to query.
* @return The score associated with `id`, or {@link Double#NaN} if there is no score.
*/
double getScore(long id);
}