/*
* Copyright Myrrix Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.myrrix.web.servlets;
import java.io.IOException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.recommender.IDRescorer;
import net.myrrix.common.MyrrixRecommender;
import net.myrrix.common.NotReadyException;
import net.myrrix.online.RescorerProvider;
/**
* <p>Responds to a GET request to {@code /mostPopularItems(?howMany=n)}
* and in turn calls
* {@link MyrrixRecommender#mostPopularItems(int)}. If {@code howMany} is not specified, defaults to
* {@link AbstractMyrrixServlet#DEFAULT_HOW_MANY}.
*
* <p>Output is as in {@link RecommendServlet}.</p>
*
* @author Sean Owen
* @since 1.0
*/
public final class MostPopularItemsServlet extends AbstractMyrrixServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
MyrrixRecommender recommender = getRecommender();
RescorerProvider rescorerProvider = getRescorerProvider();
try {
IDRescorer rescorer = rescorerProvider == null ? null :
rescorerProvider.getMostPopularItemsRescorer(recommender, getRescorerParams(request));
output(request, response, recommender.mostPopularItems(getHowMany(request), rescorer));
} catch (NotReadyException nre) {
response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE, nre.toString());
} catch (TasteException te) {
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, te.toString());
getServletContext().log("Unexpected error in " + getClass().getSimpleName(), te);
} catch (IllegalArgumentException iae) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, iae.toString());
}
}
}