Java tutorial
/* * Computoser is a music-composition algorithm and a website to present the results * Copyright (C) 2012-2014 Bozhidar Bozhanov * * Computoser is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * Computoser 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 Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with Computoser. If not, see <http://www.gnu.org/licenses/>. */ package com.music.scheduled; import java.util.Collections; import java.util.List; import javax.inject.Inject; import org.joda.time.DateTime; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.scheduling.annotation.Async; import org.springframework.scheduling.annotation.Scheduled; import org.springframework.stereotype.Component; import org.springframework.transaction.annotation.Transactional; import com.music.dao.PieceDao; import com.music.model.persistent.FeedEntry; import com.music.model.persistent.Piece; @Component public class FeedGenerator { private static final Logger logger = LoggerFactory.getLogger(FeedGenerator.class); @Inject private PieceDao dao; @Scheduled(cron = "0 0 0 * * ?") //every midnight @Transactional public void generateFeed() { logger.info("Generating feed"); DateTime now = new DateTime(); DateTime oneDayAgo = now.minusDays(1); List<Piece> pieces = dao.getPiecesInRange(oneDayAgo, now); Collections.shuffle(pieces); logger.info("Found " + pieces.size() + " eligible pieces"); int persisted = 0; for (Piece piece : pieces) { if (piece.getLikes() < 3 && piece.getLikes() > -3) { FeedEntry entry = new FeedEntry(); entry.setInclusionTime(now); entry.setPiece(piece); dao.persist(entry); persisted++; } if (persisted == 2) { break; } } logger.info("Inserted " + persisted + " entries into the feed"); } @Transactional @Async public void triggerFeedGeneration() { try { generateFeed(); } catch (Exception ex) { logger.warn("Problem generating feed", ex); } } }