/*
 * LensKit, an open source recommender systems toolkit.
 * Copyright 2010-2013 Regents of the University of Minnesota and contributors
 * 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.grouplens.lenskit.eval.data;

import org.grouplens.grapht.util.Providers;
import org.grouplens.lenskit.cursors.Cursors;
import org.grouplens.lenskit.data.dao.EventCollectionDAO;
import org.grouplens.lenskit.data.dao.EventDAO;
import org.grouplens.lenskit.data.dao.SimpleFileRatingDAO;
import org.grouplens.lenskit.data.event.Rating;
import org.grouplens.lenskit.data.pref.PreferenceDomain;
import org.grouplens.lenskit.util.SoftMemoizingProvider;
import org.grouplens.lenskit.util.io.CompressionMode;

import javax.annotation.Nonnull;
import javax.inject.Provider;
import java.io.File;
import java.util.List;

/**
 * @author <a href="http://www.grouplens.org">GroupLens Research</a>
 */
public class CSVDataSource extends AbstractDataSource {
    final String name;
    final Provider<EventDAO> provider;
    final File sourceFile;
    final PreferenceDomain domain;
    final String delimiter;

    CSVDataSource(String name, File file, String delim, boolean cache, PreferenceDomain pdom) {
        this.name = name;
        sourceFile = file;
        domain = pdom;
        delimiter = delim;

        final EventDAO fileDao = new SimpleFileRatingDAO(file, delim, CompressionMode.AUTO);

        if (cache) {
            provider = new SoftMemoizingProvider<EventDAO>() {
                @Nonnull
                @Override
                protected EventDAO newValue() {
                    List<Rating> ratings = Cursors.makeList(fileDao.streamEvents(Rating.class));
                    return new EventCollectionDAO(ratings);
                }
            };
        } else {
            provider = Providers.of(fileDao);
        }
    }

    @Override
    public String getName() {
        return name;
    }

    public File getFile() {
        return sourceFile;
    }

    public String getDelimiter() {
        return delimiter;
    }

    @Override
    public PreferenceDomain getPreferenceDomain() {
        return domain;
    }

    @Override
    public long lastModified() {
        return sourceFile.exists() ? sourceFile.lastModified() : -1L;
    }

    @Override
    public Provider<EventDAO> getEventDAOProvider() {
        return provider;
    }
}

@@ -1624,16 +1624,214 @@
 t;%0A%0A/**%0A
+ * Data source backed by a CSV file.  Use %7B@link CSVDataSourceBuilder%7D to configure and build one%0A * of these, or the %3Ccode%3Ecsvfile%3C/code%3E command in an eval script.%0A *%0A * @see CSVDataSourceBuilder%0A
  * @auth

Add documentation link to CSV data source (#364)