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.service;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.util.ArrayList;
  import java.util.Comparator;
  import java.util.List;
  import java.util.TreeSet;
  
  import javax.inject.Inject;
  
  import org.springframework.stereotype.Service;
  import org.springframework.transaction.annotation.Transactional;
  
  import com.google.common.primitives.Ints;
  import com.google.common.primitives.Longs;
  import com.music.dao.PieceDao;
  import com.music.model.persistent.Piece;
  import com.music.model.persistent.PiecePack;
  
  @Service
  public class PiecePackService {
  
      @Inject
      private PieceDao dao;
  
      @Inject
      private PieceService pieceService;
  
      @Transactional(readOnly=true)
      public List<PiecePack> getPiecePacks() {
          List<PiecePack> packs = dao.listOrdered(PiecePack.class, "priority");
          // order pieces in memory, by likes
          for (PiecePack pack : packs) {
              TreeSet<Piece> pieces = new TreeSet<>(pieceComparator);
              pieces.addAll(pack.getPieces());
              pack.setPieces(pieces);
          }
          return packs;
      }
  
      public static final Comparator<Piece> pieceComparator = new Comparator<Piece>() {
          @Override
          public int compare(Piece o1, Piece o2) {
              int result = Ints.compare(o2.getLikes(), o1.getLikes());
              if (result == 0) {
                  result = Longs.compare(o2.getId(), o1.getId());
              }
              return result;
          }
      };
  
      @Transactional(readOnly=true)
      public List<PiecePack> getPiecePacks(ArrayList<Long> ids) {
          return dao.getByIds(PiecePack.class, ids);
      }
  
      @Transactional
      public void download(long packId, OutputStream out) throws IOException {
          PiecePack pack = getPack(packId);
          pack.setDownloads(pack.getDownloads() + 1);
          dao.persist(pack);
          pieceService.downloadPieces(out, pack.getPieces());
      }
  
      @Transactional(readOnly=true)
      public PiecePack getPack(long id) {
          return dao.getById(PiecePack.class, id);
      }
  }
  