/*
* 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.grouplens.lenskit.eval.data;
import com.google.common.base.Supplier;
import com.google.common.base.Suppliers;
import org.grouplens.lenskit.core.LenskitConfiguration;
import org.grouplens.lenskit.data.dao.*;
import org.grouplens.lenskit.data.pref.PreferenceDomain;
import org.grouplens.lenskit.eval.traintest.CachingDAOProvider;
import org.grouplens.lenskit.util.MoreSuppliers;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Base class to help implement data sources.
*
* @since 2.0
* @author <a href="http://www.grouplens.org">GroupLens Research</a>
*/
public abstract class AbstractDataSource implements DataSource {
protected final Logger logger = LoggerFactory.getLogger(getClass());
private final Supplier<EventDAO> eventDAOSupplier = new Supplier<EventDAO>() {
@Override
public EventDAO get() {
return getEventDAO();
}
};
private final Supplier<UserDAO> userDAOCache =
MoreSuppliers.softMemoize(Suppliers.compose(PrefetchingUserDAO.wrapper(),
eventDAOSupplier));
private final Supplier<UserEventDAO> userEventDAOCache =
MoreSuppliers.softMemoize(Suppliers.compose(PrefetchingUserEventDAO.wrapper(),
eventDAOSupplier));
private final Supplier<ItemDAO> itemDAOCache =
MoreSuppliers.softMemoize(Suppliers.compose(PrefetchingItemDAO.wrapper(),
eventDAOSupplier));
private final Supplier<ItemEventDAO> itemEventDAOCache =
MoreSuppliers.softMemoize(Suppliers.compose(PrefetchingItemEventDAO.wrapper(),
eventDAOSupplier));
/**
* Default user-event DAO implementation. If the {@linkplain #getEventDAO() event DAO}
* implements {@link UserEventDAO}, it is returned directly; otherwise, a new {@link PrefetchingUserEventDAO}
* is created.
*
* @return The user-event DAO.
*/
@Override
public UserEventDAO getUserEventDAO() {
return userEventDAOCache.get();
}
/**
* Default item-event DAO implementation. If the {@linkplain #getEventDAO() event DAO}
* implements {@link ItemEventDAO}, it is returned directly; otherwise, a new {@link PrefetchingItemEventDAO}
* is created.
*
* @return The item-event DAO.
*/
@Override
public ItemEventDAO getItemEventDAO() {
return itemEventDAOCache.get();
}
/**
* Default item DAO implementation. If the {@linkplain #getEventDAO() event DAO}
* implements {@link ItemDAO}, it is returned directly; otherwise, a new {@link PrefetchingItemDAO}
* is created.
*
* @return The user-event DAO.
*/
@Override
public ItemDAO getItemDAO() {
return itemDAOCache.get();
}
/**
* Default user DAO implementation. If the {@linkplain #getEventDAO() event DAO}
* implements {@link UserDAO}, it is returned directly; otherwise, a new {@link PrefetchingUserDAO}
* is created.
*
* @return The user-event DAO.
*/
@Override
public UserDAO getUserDAO() {
return userDAOCache.get();
}
@Override
public void configure(LenskitConfiguration config) {
logger.debug("generating configuration for {}", this);
config.addComponent(getEventDAO());
PreferenceDomain dom = getPreferenceDomain();
if (dom != null) {
logger.debug("using preference domain {}", dom);
config.addComponent(dom);
}
config.bind(PrefetchingUserDAO.class)
.toProvider(CachingDAOProvider.User.class);
config.bind(PrefetchingUserEventDAO.class)
.toProvider(CachingDAOProvider.UserEvent.class);
config.bind(PrefetchingItemDAO.class)
.toProvider(CachingDAOProvider.Item.class);
config.bind(PrefetchingItemEventDAO.class)
.toProvider(CachingDAOProvider.ItemEvent.class);
}
}