code: /*
   * 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);
          }
      }
  
  }
  