src/main/java/net/pterodactylus/demoscenemusic/data/DataManager.java

   1 /*
   2  * DemosceneMusic - DataManager.java - Copyright © 2012 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.demoscenemusic.data;
  19
  20 import java.sql.ResultSet;
  21 import java.sql.SQLException;
  22 import java.util.Collection;
  23 import java.util.EnumMap;
  24 import java.util.HashSet;
  25 import java.util.List;
  26 import java.util.Map;
  27 import java.util.Map.Entry;
  28 import java.util.UUID;
  29 import java.util.concurrent.Callable;
  30
  31 import net.pterodactylus.demoscenemusic.data.Track.Relationship;
  32 import net.pterodactylus.util.collection.Memoizer;
  33 import net.pterodactylus.util.database.Database;
  34 import net.pterodactylus.util.database.DatabaseException;
  35 import net.pterodactylus.util.database.Field;
  36 import net.pterodactylus.util.database.Join;
  37 import net.pterodactylus.util.database.Join.JoinType;
  38 import net.pterodactylus.util.database.ObjectCreator;
  39 import net.pterodactylus.util.database.ObjectCreator.StringCreator;
  40 import net.pterodactylus.util.database.OrderField;
  41 import net.pterodactylus.util.database.Parameter.IntegerParameter;
  42 import net.pterodactylus.util.database.Parameter.StringParameter;
  43 import net.pterodactylus.util.database.Query;
  44 import net.pterodactylus.util.database.Query.Type;
  45 import net.pterodactylus.util.database.ResultProcessor;
  46 import net.pterodactylus.util.database.ValueField;
  47 import net.pterodactylus.util.database.ValueFieldWhereClause;
  48
  49 /**
  50  * Interface between the database and the application.
  51  *
  52  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  53  */
  54 public class DataManager {
  55
  56         /** The artist object creator. */
  57         @SuppressWarnings("synthetic-access")
  58         private final ObjectCreator<Artist> artistCreator = new ArtistCreator();
  59
  60         /** The group object creator. */
  61         @SuppressWarnings("synthetic-access")
  62         private final ObjectCreator<Group> groupCreator = new GroupCreator();
  63
  64         /** The track object creator. */
  65         @SuppressWarnings("synthetic-access")
  66         private final ObjectCreator<Track> trackCreator = new TrackCreator();
  67
  68         /** The track object creator. */
  69         @SuppressWarnings("synthetic-access")
  70         private final ObjectCreator<TrackDerivative> trackDerivativeCreator = new TrackDerivativeCreator();
  71
  72         /** The style object creator. */
  73         @SuppressWarnings("synthetic-access")
  74         private final ObjectCreator<Style> styleCreator = new StyleCreator();
  75
  76         /** The party object creator. */
  77         @SuppressWarnings("synthetic-access")
  78         private final ObjectCreator<Party> partyCreator = new PartyCreator();
  79
  80         /** The {@link User} object creator. */
  81         @SuppressWarnings("synthetic-access")
  82         private final ObjectCreator<User> userCreator = new UserCreator();
  83
  84         /** The database. */
  85         private final Database database;
  86
  87         /**
  88          * Creates a new data manager.
  89          *
  90          * @param database
  91          *            The database to operate on
  92          */
  93         public DataManager(Database database) {
  94                 this.database = database;
  95         }
  96
  97         /**
  98          * Returns all artists.
  99          *
 100          * @return All artists
 101          * @throws DatabaseException
 102          *             if a database error occurs
 103          */
 104         public Collection<Artist> getAllArtists() throws DatabaseException {
 105                 Query query = new Query(Type.SELECT, "ARTISTS");
 106                 query.addField(new Field("ARTISTS.*"));
 107                 return loadArtistProperties(database.getMultiple(query, artistCreator));
 108         }
 109
 110         /**
 111          * Returns the artist with the given ID.
 112          *
 113          * @param id
 114          *            The ID of the artist
 115          * @return The artist with the given ID, or {@code null} if there is no
 116          *         artist with the given ID
 117          * @throws DatabaseException
 118          *             if a database error occurs
 119          */
 120         public Artist getArtistById(String id) throws DatabaseException {
 121                 Query query = new Query(Type.SELECT, "ARTISTS");
 122                 query.addField(new Field("ARTISTS.*"));
 123                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ARTISTS.ID", new StringParameter(id))));
 124                 return loadArtistProperties(database.getSingle(query, artistCreator));
 125         }
 126
 127         /**
 128          * Returns all artists that belong to the group with the given ID.
 129          *
 130          * @param groupId
 131          *            The ID of the group
 132          * @return All artists belonging to the given group
 133          * @throws DatabaseException
 134          *             if a database error occurs
 135          */
 136         public Collection<Artist> getArtistsByGroup(String groupId) throws DatabaseException {
 137                 Query query = new Query(Type.SELECT, "ARTISTS");
 138                 query.addField(new Field("ARTISTS.*"));
 139                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("ARTISTS.ID"), new Field("GROUP_ARTISTS.ARTIST")));
 140                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.GROUP_", new StringParameter(groupId))));
 141                 return loadArtistProperties(database.getMultiple(query, artistCreator));
 142         }
 143
 144         /**
 145          * Returns all artists involved in the track with the given ID.
 146          *
 147          * @param trackId
 148          *            The ID of the track
 149          * @return All artists involved in the track, in preferred order
 150          * @throws DatabaseException
 151          *             if a database error occurs
 152          */
 153         public List<Artist> getArtistsByTrack(String trackId) throws DatabaseException {
 154                 Query query = new Query(Type.SELECT, "ARTISTS");
 155                 query.addField(new Field("ARTISTS.*"));
 156                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACK_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 157                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(trackId))));
 158                 query.addOrderField(new OrderField(new Field("TRACK_ARTISTS.DISPLAY_ORDER")));
 159                 return loadArtistProperties(database.getMultiple(query, artistCreator));
 160         }
 161
 162         /**
 163          * Creates a new artist with the given name.
 164          *
 165          * @param name
 166          *            The name of the artist
 167          * @return The created artist
 168          * @throws DatabaseException
 169          *             if a database error occurs
 170          */
 171         public Artist createArtist(String name) throws DatabaseException {
 172                 Query query = new Query(Type.INSERT, "ARTISTS");
 173                 String id = UUID.randomUUID().toString();
 174                 query.addValueField(new ValueField("ID", new StringParameter(id)));
 175                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
 176                 database.insert(query);
 177                 return loadArtistProperties(getArtistById(id));
 178         }
 179
 180         /**
 181          * Saves the given artist.
 182          *
 183          * @param artist
 184          *            The artist to save
 185          * @throws DatabaseException
 186          *             if a database error occurs
 187          */
 188         public void saveArtist(Artist artist) throws DatabaseException {
 189                 Query query = new Query(Type.UPDATE, "ARTISTS");
 190                 query.addValueField(new ValueField("NAME", new StringParameter(artist.getName())));
 191                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ID", new StringParameter(artist.getId()))));
 192                 database.update(query);
 193                 saveArtistProperties(artist);
 194         }
 195
 196         /**
 197          * Saves the properties of the given artist.
 198          *
 199          * @param artist
 200          *            The artist whose properties to save
 201          * @throws DatabaseException
 202          *             if a database error occurs
 203          */
 204         public void saveArtistProperties(Artist artist) throws DatabaseException {
 205                 saveProperties(artist.getProperties(), "ARTIST_PROPERTIES", "ARTIST", artist.getId());
 206         }
 207
 208         /**
 209          * Saves the given properties to the given table for the given principal.
 210          *
 211          * @param properties
 212          *            The properties to save
 213          * @param table
 214          *            The table in which to save the properties
 215          * @param type
 216          *            The type of the principal (e. g. “ARTIST” or “TRACK”)
 217          * @param id
 218          *            The ID of the principial
 219          * @throws DatabaseException
 220          *             if a database error occurs
 221          */
 222         public void saveProperties(Properties properties, String table, String type, String id) throws DatabaseException {
 223                 if (!properties.isDirty()) {
 224                         return;
 225                 }
 226                 Query query = new Query(Type.DELETE, table);
 227                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(id))));
 228                 database.update(query);
 229                 for (Entry<String, String> property : properties) {
 230                         Query insertQuery = new Query(Type.INSERT, table);
 231                         insertQuery.addValueField(new ValueField(type, new StringParameter(id)));
 232                         insertQuery.addValueField(new ValueField("PROPERTY", new StringParameter(property.getKey())));
 233                         insertQuery.addValueField(new ValueField("VALUE", new StringParameter(property.getValue())));
 234                         database.insert(insertQuery);
 235                 }
 236                 properties.resetDirty();
 237         }
 238
 239         /**
 240          * Loads the properties for an artist.
 241          *
 242          * @param artist
 243          *            The artist to load the properties for
 244          * @return The artist
 245          * @throws DatabaseException
 246          *             if a database error occurs
 247          */
 248         public Artist loadArtistProperties(final Artist artist) throws DatabaseException {
 249                 return loadProperties(artist, "ARTIST_PROPERTIES", "ARTIST");
 250         }
 251
 252         /**
 253          * Loads the properties of all given artists.
 254          *
 255          * @param artists
 256          *            The artists to load the properties for
 257          * @return The list of artists
 258          * @throws DatabaseException
 259          *             if a database error occurs
 260          */
 261         public List<Artist> loadArtistProperties(List<Artist> artists) throws DatabaseException {
 262                 for (Artist artist : artists) {
 263                         loadArtistProperties(artist);
 264                 }
 265                 return artists;
 266         }
 267
 268         /**
 269          * Returns all remix artists involved in the track with the given ID.
 270          *
 271          * @param trackId
 272          *            The ID of the track
 273          * @return All remix artists involved in the track, in preferred order
 274          * @throws DatabaseException
 275          *             if a database error occurs
 276          */
 277         public List<Artist> getRemixArtistsByTrack(String trackId) throws DatabaseException {
 278                 Query query = new Query(Type.SELECT, "ARTISTS");
 279                 query.addField(new Field("ARTISTS.*"));
 280                 query.addJoin(new Join(JoinType.INNER, "TRACK_REMIX_ARTISTS", new Field("TRACK_REMIX_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 281                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_REMIX_ARTISTS.TRACK", new StringParameter(trackId))));
 282                 query.addOrderField(new OrderField(new Field("TRACK_REMIX_ARTISTS.DISPLAY_ORDER")));
 283                 return database.getMultiple(query, artistCreator);
 284         }
 285
 286         /**
 287          * Returns all related tracks for the track with the given ID.
 288          *
 289          * @param trackId
 290          *            The ID of the tracks
 291          * @return A mapping from relationship to all tracks that match the relation
 292          * @throws DatabaseException
 293          *             if a database error occurs
 294          */
 295         public Map<Relationship, Collection<Track>> getRelatedTracksByTrack(String trackId) throws DatabaseException {
 296                 Query query = new Query(Type.SELECT, "TRACKS");
 297                 query.addField(new Field("TRACKS.*"));
 298                 query.addField(new Field("TRACK_RELATIONS.*"));
 299                 query.addJoin(new Join(JoinType.INNER, "TRACK_RELATIONS", new Field("TRACK_RELATIONS.TRACK"), new Field("TRACK_RELATIONS.RELATED_TRACK")));
 300                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_RELATIONS.TRACK", new StringParameter(trackId))));
 301                 final Map<Relationship, Collection<Track>> relatedTracks = new EnumMap<Relationship, Collection<Track>>(Relationship.class);
 302                 database.process(query, new ResultProcessor() {
 303
 304                         @Override
 305                         @SuppressWarnings("synthetic-access")
 306                         public void processResult(ResultSet resultSet) throws SQLException {
 307                                 Track track = trackCreator.createObject(resultSet);
 308                                 Relationship relationship = Relationship.valueOf(resultSet.getString("TRACK_RELATIONS.RELATIONSHIP"));
 309                                 if (!relatedTracks.containsKey(relationship)) {
 310                                         relatedTracks.put(relationship, new HashSet<Track>());
 311                                 }
 312                                 relatedTracks.get(relationship).add(track);
 313                         }
 314                 });
 315                 return relatedTracks;
 316         }
 317
 318         /**
 319          * Returns the track with the given ID.
 320          *
 321          * @param id
 322          *            The ID of the track
 323          * @return The track with the given ID, or {@code null} if there is no such
 324          *         track
 325          * @throws DatabaseException
 326          *             if a database error occurs
 327          */
 328         public Track getTrackById(String id) throws DatabaseException {
 329                 Query query = new Query(Type.SELECT, "TRACKS");
 330                 query.addField(new Field("TRACKS.*"));
 331                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(id))));
 332                 return loadTrackProperties(database.getSingle(query, trackCreator));
 333         }
 334
 335         /**
 336          * Returns the track that contains the derivative with the given ID.
 337          *
 338          * @param id
 339          *            The ID of the track derivative
 340          * @return The track the derivative belongs to, or {@code null} if there is
 341          *         no such track
 342          * @throws DatabaseException
 343          *             if a database error occurs
 344          */
 345         public Track getTrackByDerivativeId(String id) throws DatabaseException {
 346                 Query query = new Query(Type.SELECT, "TRACKS");
 347                 query.addField(new Field("TRACKS.*"));
 348                 query.addJoin(new Join(JoinType.INNER, "TRACK_DERIVATIVES", new Field("TRACK_DERIVATIVES.TRACK"), new Field("TRACKS.ID")));
 349                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id))));
 350                 return loadTrackProperties(database.getSingle(query, trackCreator));
 351         }
 352
 353         /**
 354          * Returns all tracks by the artist with the given ID.
 355          *
 356          * @param artistId
 357          *            The ID of the artist
 358          * @return All tracks by the given artist
 359          * @throws DatabaseException
 360          *             if a database error occurs
 361          */
 362         public Collection<Track> getTracksByArtist(String artistId) throws DatabaseException {
 363                 Query query = new Query(Type.SELECT, "TRACKS");
 364                 query.addField(new Field("TRACKS.*"));
 365                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACKS.ID"), new Field("TRACK_ARTISTS.TRACK")));
 366                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(artistId))));
 367                 return loadTrackProperties(database.getMultiple(query, trackCreator));
 368         }
 369
 370         /**
 371          * Returns all tracks that were released at the party with the given ID.
 372          *
 373          * @param partyId
 374          *            The ID of the party
 375          * @return All tracks that were released at the given party
 376          * @throws DatabaseException
 377          *             if a database error occurs
 378          */
 379         public Collection<Track> getTracksByParty(String partyId) throws DatabaseException {
 380                 Query query = new Query(Type.SELECT, "TRACKS");
 381                 query.addField(new Field("TRACKS.*"));
 382                 query.addJoin(new Join(JoinType.INNER, "PARTY_TRACKS", new Field("PARTY_TRACKS.TRACK"), new Field("TRACKS.ID")));
 383                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTY_TRACKS.PARTY", new StringParameter(partyId))));
 384                 return loadTrackProperties(database.getMultiple(query, trackCreator));
 385         }
 386
 387         /**
 388          * Loads the properties for the given track.
 389          *
 390          * @param track
 391          *            The track for which to load the properties
 392          * @return The track with the properties loaded
 393          * @throws DatabaseException
 394          *             if a database error occurs
 395          */
 396         public Track loadTrackProperties(Track track) throws DatabaseException {
 397                 return loadProperties(track, "TRACK_PROPERTIES", "TRACK");
 398         }
 399
 400         /**
 401          * Loads the properties for the given tracks.
 402          *
 403          * @param tracks
 404          *            The tracks for which to load the properties
 405          * @return The tracks with the properties loaded
 406          * @throws DatabaseException
 407          *             if a database error occurs
 408          */
 409         public List<Track> loadTrackProperties(List<Track> tracks) throws DatabaseException {
 410                 for (Track track : tracks) {
 411                         loadTrackProperties(track);
 412                 }
 413                 return tracks;
 414         }
 415
 416         /**
 417          * Creates a new track with the given name.
 418          *
 419          * @param name
 420          *            The name of the track
 421          * @return The created track
 422          * @throws DatabaseException
 423          *             if a database error occurs
 424          */
 425         public Track createTrack(String name) throws DatabaseException {
 426                 Query query = new Query(Type.INSERT, "TRACKS");
 427                 String id = UUID.randomUUID().toString();
 428                 query.addValueField(new ValueField("ID", new StringParameter(id)));
 429                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
 430                 database.insert(query);
 431                 return getTrackById(id);
 432         }
 433
 434         /**
 435          * Saves the given track. This also saves all relationships of the track.
 436          *
 437          * @param track
 438          *            The track to save
 439          * @throws DatabaseException
 440          *             if a database error occurs
 441          */
 442         public void saveTrack(Track track) throws DatabaseException {
 443                 Query query = new Query(Type.UPDATE, "TRACKS");
 444                 query.addValueField(new ValueField("TRACKS.NAME", new StringParameter(track.getName())));
 445                 query.addValueField(new ValueField("TRACKS.REMIX", new StringParameter(track.getRemix())));
 446                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(track.getId()))));
 447                 database.update(query);
 448                 /* store artist information. */
 449                 track.getArtists(); /* prefetch artists. */
 450                 query = new Query(Type.DELETE, "TRACK_ARTISTS");
 451                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(track.getId()))));
 452                 database.update(query);
 453                 for (int index = 0; index < track.getArtists().size(); ++index) {
 454                         query = new Query(Type.INSERT, "TRACK_ARTISTS");
 455                         query.addValueField(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(track.getId())));
 456                         query.addValueField(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(track.getArtists().get(index).getId())));
 457                         query.addValueField(new ValueField("TRACK_ARTISTS.DISPLAY_ORDER", new IntegerParameter(index + 1)));
 458                         database.insert(query);
 459                 }
 460                 /* store properties. */
 461                 saveProperties(track.getProperties(), "TRACK_PROPERTIES", "TRACK", track.getId());
 462         }
 463
 464         /**
 465          * Returns the derivative with the given ID.
 466          *
 467          * @param id
 468          *            The ID of the derivatives to load
 469          * @return The derivative with the given ID
 470          * @throws DatabaseException
 471          *             if a database error occurs
 472          */
 473         public TrackDerivative getTrackDerivativeById(String id) throws DatabaseException {
 474                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 475                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 476                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id))));
 477                 return loadTrackDerivativeProperties(database.getSingle(query, trackDerivativeCreator));
 478         }
 479
 480         /**
 481          * Returns the derivatives for the given track.
 482          *
 483          * @param trackId
 484          *            The track ID to get the derivatives for
 485          * @return The derivatives for the given track
 486          * @throws DatabaseException
 487          *             if a database error occurs
 488          */
 489         public Collection<TrackDerivative> getTrackDerivativesByTrack(String trackId) throws DatabaseException {
 490                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 491                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 492                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(trackId))));
 493                 return loadTrackDerivativeProperties(database.getMultiple(query, trackDerivativeCreator));
 494         }
 495
 496         /**
 497          * Creates a new derivative for the given track.
 498          *
 499          * @param track
 500          *            The track to create the derivative for
 501          * @return The created derivative
 502          * @throws DatabaseException
 503          *             if a database error occurs
 504          */
 505         public TrackDerivative createTrackDerivative(Track track) throws DatabaseException {
 506                 Query query = new Query(Type.INSERT, "TRACK_DERIVATIVES");
 507                 String id = UUID.randomUUID().toString();
 508                 query.addValueField(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id)));
 509                 query.addValueField(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(track.getId())));
 510                 database.insert(query);
 511                 return getTrackDerivativeById(id);
 512         }
 513
 514         /**
 515          * Loads the properties for the given track derivative.
 516          *
 517          * @param trackDerivative
 518          *            The track derivative to load the properties for
 519          * @return The track derivative with its properties loaded
 520          * @throws DatabaseException
 521          *             if a database error occurs
 522          */
 523         public TrackDerivative loadTrackDerivativeProperties(TrackDerivative trackDerivative) throws DatabaseException {
 524                 return loadProperties(trackDerivative, "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE");
 525         }
 526
 527         /**
 528          * Loads the properties for the given track derivatives.
 529          *
 530          * @param trackDerivatives
 531          *            The track derivatives to load the properties for
 532          * @return The track derivatives with their properties loaded
 533          * @throws DatabaseException
 534          *             if a database error occurs
 535          */
 536         public List<TrackDerivative> loadTrackDerivativeProperties(List<TrackDerivative> trackDerivatives) throws DatabaseException {
 537                 for (TrackDerivative trackDerivative : trackDerivatives) {
 538                         loadTrackDerivativeProperties(trackDerivative);
 539                 }
 540                 return trackDerivatives;
 541         }
 542
 543         /**
 544          * Saves the given track derivative. As a track derivative does not have any
 545          * attributes of its own only its properties are saved.
 546          *
 547          * @param trackDerivative
 548          *            The track derivative to save
 549          * @throws DatabaseException
 550          *             if a database error occurs
 551          */
 552         public void saveTrackDerivate(TrackDerivative trackDerivative) throws DatabaseException {
 553                 saveProperties(trackDerivative.getProperties(), "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE", trackDerivative.getId());
 554         }
 555
 556         /**
 557          * Removes the given track derivative and all its properties from the
 558          * database.
 559          *
 560          * @param trackDerivative
 561          *            The track derivative to remove
 562          * @throws DatabaseException
 563          *             if a database error occurs
 564          */
 565         public void removeTrackDerivative(TrackDerivative trackDerivative) throws DatabaseException {
 566                 Query query = new Query(Type.DELETE, "TRACK_DERIVATIVES");
 567                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(trackDerivative.getId()))));
 568                 database.update(query);
 569                 /* remove the properties. */
 570                 saveProperties(new Properties().set("dirty", "true").removeAll(), "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE", trackDerivative.getId());
 571         }
 572
 573         /**
 574          * Returns all groups the artist with the given ID belongs to.
 575          *
 576          * @param artistId
 577          *            The ID of the artist
 578          * @return All groups the artist belongs to
 579          * @throws DatabaseException
 580          *             if a database error occurs
 581          */
 582         public Collection<Group> getGroupsByArtist(String artistId) throws DatabaseException {
 583                 Query query = new Query(Type.SELECT, "GROUPS");
 584                 query.addField(new Field("GROUPS.*"));
 585                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("GROUPS.ID"), new Field("GROUP_ARTISTS.GROUP_")));
 586                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artistId))));
 587                 return database.getMultiple(query, groupCreator);
 588         }
 589
 590         /**
 591          * Returns all styles for the track with the given ID.
 592          *
 593          * @param trackId
 594          *            The ID of the track
 595          * @return All styles for the given track
 596          * @throws DatabaseException
 597          *             if a database error occurs
 598          */
 599         public Collection<Style> getStylesByTrack(String trackId) throws DatabaseException {
 600                 Query query = new Query(Type.SELECT, "STYLES");
 601                 query.addField(new Field("STYLES.*"));
 602                 query.addJoin(new Join(JoinType.INNER, "TRACK_STYLES", new Field("STYLES.ID"), new Field("TRACK_STYLES.STYLE")));
 603                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_STYLES.TRACK", new StringParameter(trackId))));
 604                 return database.getMultiple(query, styleCreator);
 605         }
 606
 607         /**
 608          * Returns all parties.
 609          *
 610          * @return All parties
 611          * @throws DatabaseException
 612          *             if a database error occurs
 613          */
 614         public Collection<Party> getAllParties() throws DatabaseException {
 615                 Query query = new Query(Type.SELECT, "PARTIES");
 616                 query.addField(new Field("PARTIES.*"));
 617                 return loadPartyProperties(database.getMultiple(query, partyCreator));
 618         }
 619
 620         /**
 621          * Returns all parties that the track with the given ID was released at.
 622          *
 623          * @param trackId
 624          *            The ID of the track
 625          * @return All parties the track was released at
 626          * @throws DatabaseException
 627          *             if a database error occurs
 628          */
 629         public Collection<Party> getPartiesByTrackId(String trackId) throws DatabaseException {
 630                 Query query = new Query(Type.SELECT, "PARTIES");
 631                 query.addField(new Field("PARTIES.*"));
 632                 query.addJoin(new Join(JoinType.INNER, "PARTY_TRACKS", new Field("PARTY_TRACKS.PARTY"), new Field("PARTIES.ID")));
 633                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTY_TRACKS.TRACK", new StringParameter(trackId))));
 634                 return loadPartyProperties(database.getMultiple(query, partyCreator));
 635         }
 636
 637         /**
 638          * Returns the party with the given ID.
 639          *
 640          * @param partyId
 641          *            The ID of the party
 642          * @return The party with the given ID
 643          * @throws DatabaseException
 644          *             if a database error occurs
 645          */
 646         public Party getPartyById(String partyId) throws DatabaseException {
 647                 Query query = new Query(Type.SELECT, "PARTIES");
 648                 query.addField(new Field("PARTIES.*"));
 649                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTIES.ID", new StringParameter(partyId))));
 650                 return loadPartyProperties(database.getSingle(query, partyCreator));
 651         }
 652
 653         /**
 654          * Loads the properties of the given party.
 655          *
 656          * @param party
 657          *            The party to load the properties for
 658          * @return The party with its properties loaded
 659          * @throws DatabaseException
 660          *             if a database error occurs
 661          */
 662         public Party loadPartyProperties(Party party) throws DatabaseException {
 663                 return loadProperties(party, "PARTY_PROPERTIES", "PARTY");
 664         }
 665
 666         /**
 667          * Loads the properties of the given parties.
 668          *
 669          * @param parties
 670          *            The parties to load the properties for
 671          * @return The parties with their properties loaded
 672          * @throws DatabaseException
 673          *             if a database error occurs
 674          */
 675         public List<Party> loadPartyProperties(List<Party> parties) throws DatabaseException {
 676                 for (Party party : parties) {
 677                         loadPartyProperties(party);
 678                 }
 679                 return parties;
 680         }
 681
 682         /**
 683          * Saves the given party.
 684          *
 685          * @param party
 686          *            The party to save
 687          * @throws DatabaseException
 688          *             if a database error occurs
 689          */
 690         public void saveParty(Party party) throws DatabaseException {
 691                 Query query = new Query(Type.UPDATE, "PARTIES");
 692                 query.addValueField(new ValueField("NAME", new StringParameter(party.getName())));
 693                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ID", new StringParameter(party.getId()))));
 694                 database.update(query);
 695                 savePartyProperties(party);
 696         }
 697
 698         /**
 699          * Saves the properties of the given party.
 700          *
 701          * @param party
 702          *            The party whose properties to save
 703          * @throws DatabaseException
 704          *             if a database error occurs
 705          */
 706         public void savePartyProperties(Party party) throws DatabaseException {
 707                 saveProperties(party.getProperties(), "PARTY_PROPERTIES", "PARTY", party.getId());
 708         }
 709
 710         /**
 711          * Creates a new party with the given name.
 712          *
 713          * @param name
 714          *            The name of the party
 715          * @return The new party
 716          * @throws DatabaseException
 717          *             if a database error occurs
 718          */
 719         public Party createParty(String name) throws DatabaseException {
 720                 Query query = new Query(Type.INSERT, "PARTIES");
 721                 String id = UUID.randomUUID().toString();
 722                 query.addValueField(new ValueField("ID", new StringParameter(id)));
 723                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
 724                 database.insert(query);
 725                 return getPartyById(id);
 726         }
 727
 728         /**
 729          * Returns the user with the given name.
 730          *
 731          * @param username
 732          *            The name of the user
 733          * @return The user, or {@code null} if the user does not exist
 734          * @throws DatabaseException
 735          *             if a database error occurs
 736          */
 737         public User getUserByName(String username) throws DatabaseException {
 738                 Query query = new Query(Type.SELECT, "USERS");
 739                 query.addField(new Field("USERS.*"));
 740                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USERS.NAME", new StringParameter(username))));
 741                 return database.getSingle(query, userCreator);
 742         }
 743
 744         /**
 745          * Returns the user connected with the given OpenID.
 746          *
 747          * @param openId
 748          *            The OpenID to find the user for
 749          * @return The user connected with the given OpenID, or {@code null} if
 750          *         there is no such user
 751          * @throws DatabaseException
 752          *             if a database error occurs
 753          */
 754         public User getUserByOpenId(String openId) throws DatabaseException {
 755                 Query query = new Query(Type.SELECT, "USERS");
 756                 query.addField(new Field("USERS.*"));
 757                 query.addJoin(new Join(JoinType.INNER, "USER_OPENIDS", new Field("USER_OPENIDS.USER"), new Field("USERS.ID")));
 758                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.OPENID", new StringParameter(openId))));
 759                 return database.getSingle(query, userCreator);
 760         }
 761
 762         /**
 763          * Returns all OpenIDs connected with the user with the given ID.
 764          *
 765          * @param userId
 766          *            The ID of the user
 767          * @return All OpenIDs connected with the given user
 768          * @throws DatabaseException
 769          *             if a database error occurs
 770          */
 771         public Collection<String> getOpenIdsByUser(String userId) throws DatabaseException {
 772                 Query query = new Query(Type.SELECT, "USER_OPENIDS");
 773                 query.addField(new Field("USER_OPENIDS.*"));
 774                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.USER", new StringParameter(userId))));
 775                 return database.getMultiple(query, new StringCreator("USER_OPENIDS.OPENID"));
 776         }
 777
 778         //
 779         // PRIVATE METHODS
 780         //
 781
 782         /**
 783          * Loads the properties for the given object.
 784          *
 785          * @param <T>
 786          *            The type of the object
 787          * @param object
 788          *            The object
 789          * @param table
 790          *            The table to load the properties from
 791          * @param type
 792          *            The type of the object (“ARTIST,” “TRACK,” etc.)
 793          * @return The object with its properties loaded
 794          * @throws DatabaseException
 795          *             if a database error occurs
 796          */
 797         private <T extends Base> T loadProperties(final T object, final String table, String type) throws DatabaseException {
 798                 Query query = new Query(Type.SELECT, table);
 799                 query.addField(new Field(table + ".PROPERTY"));
 800                 query.addField(new Field(table + ".VALUE"));
 801                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(object.getId()))));
 802                 database.process(query, new ResultProcessor() {
 803
 804                         @Override
 805                         public void processResult(ResultSet resultSet) throws SQLException {
 806                                 if (resultSet.isFirst()) {
 807                                         object.getProperties().removeAll();
 808                                 }
 809                                 object.getProperties().set(resultSet.getString(table + ".PROPERTY"), resultSet.getString(table + ".VALUE"));
 810                         }
 811
 812                 });
 813                 return object;
 814         }
 815
 816         /**
 817          * {@link Artist} implementation that retrieves some attributes (such as
 818          * {@link #getGroups()}, and {@link #getTracks()}) from the
 819          * {@link DataManager} on demand.
 820          *
 821          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 822          */
 823         private class LazyArtist extends DefaultArtist {
 824
 825                 /** Memoizer for the tracks by this artist. */
 826                 private final Memoizer<Void> tracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 827
 828                         @Override
 829                         public Void call() throws DatabaseException {
 830                                 if (!hasValue("tracks")) {
 831                                         getValue("tracks", Collection.class).set(getTracksByArtist(getId()));
 832                                 }
 833                                 return null;
 834                         }
 835                 });
 836
 837                 /** Memoizer for the groups of this artist. */
 838                 private final Memoizer<Void> groupsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 839
 840                         @Override
 841                         public Void call() throws Exception {
 842                                 if (!hasValue("groups")) {
 843                                         getValue("groups", Collection.class).set(getGroupsByArtist(getId()));
 844                                 }
 845                                 return null;
 846                         }
 847
 848                 });
 849
 850                 /**
 851                  * Creates a new lazy artist.
 852                  *
 853                  * @param id
 854                  *            The ID of the artist
 855                  */
 856                 public LazyArtist(String id) {
 857                         super(id);
 858                 }
 859
 860                 //
 861                 // DEFAULTARTIST METHODS
 862                 //
 863
 864                 /**
 865                  * {@inheritDoc}
 866                  */
 867                 @Override
 868                 public Collection<Group> getGroups() {
 869                         groupsMemoizer.get();
 870                         return super.getGroups();
 871                 }
 872
 873                 /**
 874                  * {@inheritDoc}
 875                  */
 876                 @Override
 877                 public Collection<Track> getTracks() {
 878                         tracksMemoizer.get();
 879                         return super.getTracks();
 880                 }
 881
 882         }
 883
 884         /**
 885          * {@link ObjectCreator} implementation that can create {@link Artist}
 886          * objects. This specific class actually creates {@link LazyArtist}
 887          * instances.
 888          *
 889          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 890          */
 891         private class ArtistCreator implements ObjectCreator<Artist> {
 892
 893                 /**
 894                  * {@inheritDoc}
 895                  */
 896                 @Override
 897                 public Artist createObject(ResultSet resultSet) throws SQLException {
 898                         return new LazyArtist(resultSet.getString("ARTISTS.ID")).setName(resultSet.getString("ARTISTS.NAME"));
 899                 }
 900
 901         }
 902
 903         /**
 904          * {@link Group} implementation that retrieves some attributes (such as
 905          * {@link #getArtists()}) from the {@link DataManager} on demand.
 906          *
 907          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 908          */
 909         private class LazyGroup extends DefaultGroup {
 910
 911                 /** Memoizer for the artist. */
 912                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 913
 914                         @Override
 915                         public Void call() throws Exception {
 916                                 if (!hasValue("artists")) {
 917                                         getValue("artists", Collection.class).set(getArtistsByGroup(getId()));
 918                                 }
 919                                 return null;
 920                         }
 921
 922                 });
 923
 924                 /**
 925                  * Creates a new lazy group.
 926                  *
 927                  * @param id
 928                  *            The ID of the group
 929                  */
 930                 public LazyGroup(String id) {
 931                         super(id);
 932                 }
 933
 934                 //
 935                 // DEFAULTGROUP METHODS
 936                 //
 937
 938                 /**
 939                  * {@inheritDoc}
 940                  */
 941                 @Override
 942                 public Collection<Artist> getArtists() {
 943                         artistsMemoizer.get();
 944                         return super.getArtists();
 945                 }
 946
 947         }
 948
 949         /**
 950          * {@link ObjectCreator} implementation that can create {@link Group}
 951          * objects. This specific implementation creates {@link LazyGroup}
 952          * instances.
 953          *
 954          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 955          */
 956         private class GroupCreator implements ObjectCreator<Group> {
 957
 958                 /**
 959                  * {@inheritDoc}
 960                  */
 961                 @Override
 962                 public Group createObject(ResultSet resultSet) throws SQLException {
 963                         return new LazyGroup(resultSet.getString("GROUPS.ID")).setName(resultSet.getString("GROUPS.NAME")).setUrl(resultSet.getString("GROUPS.URL"));
 964                 }
 965
 966         }
 967
 968         /**
 969          * {@link Track} implementation that retrieves some attributes (such as
 970          * {@link #getArtists()}, and {@link #getStyles()}) from the
 971          * {@link DataManager} on demand.
 972          *
 973          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 974          */
 975         private class LazyTrack extends DefaultTrack {
 976
 977                 /** Memoizer for the artists. */
 978                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 979
 980                         @Override
 981                         public Void call() throws Exception {
 982                                 if (!hasValue("artists")) {
 983                                         getValue("artists", List.class).set(getArtistsByTrack(getId()));
 984                                 }
 985                                 return null;
 986                         }
 987
 988                 });
 989
 990                 /** Memoizer for the styles. */
 991                 private final Memoizer<Void> stylesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 992
 993                         @Override
 994                         public Void call() throws Exception {
 995                                 if (!hasValue("styles")) {
 996                                         getValue("styles", Collection.class).set(getStylesByTrack(getId()));
 997                                 }
 998                                 return null;
 999                         }
1000
1001                 });
1002
1003                 /** Memoizer for the remix artists. */
1004                 private final Memoizer<Void> remixArtistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
1005
1006                         @Override
1007                         public Void call() throws Exception {
1008                                 if (!hasValue("remixArtists")) {
1009                                         getValue("remixArtists", List.class).set(getRemixArtistsByTrack(getId()));
1010                                 }
1011                                 return null;
1012                         }
1013
1014                 });
1015
1016                 /** Memoizer for the track derivatives. */
1017                 private final Memoizer<Void> derivativesMemoizer = new Memoizer<Void>(new Callable<Void>() {
1018
1019                         @Override
1020                         public Void call() throws Exception {
1021                                 if (!hasValue("derivatives")) {
1022                                         getValue("derivatives", Collection.class).set(getTrackDerivativesByTrack(getId()));
1023                                 }
1024                                 return null;
1025                         }
1026
1027                 });
1028
1029                 /** Memoizer for the related tracks. */
1030                 private final Memoizer<Void> relatedTracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
1031
1032                         @Override
1033                         public Void call() throws Exception {
1034                                 if (!hasValue("relatedTracks")) {
1035                                         getValue("relatedTracks", Map.class).set(getRelatedTracksByTrack(getId()));
1036                                 }
1037                                 return null;
1038                         }
1039
1040                 });
1041
1042                 /**
1043                  * Creates a new track.
1044                  *
1045                  * @param id
1046                  *            The ID of the track
1047                  */
1048                 public LazyTrack(String id) {
1049                         super(id);
1050                 }
1051
1052                 //
1053                 // DEFAULTTRACK METHODS
1054                 //
1055
1056                 /**
1057                  * {@inheritDoc}
1058                  */
1059                 @Override
1060                 public List<Artist> getArtists() {
1061                         artistsMemoizer.get();
1062                         return super.getArtists();
1063                 }
1064
1065                 /**
1066                  * {@inheritDoc}
1067                  */
1068                 @Override
1069                 public Collection<Style> getStyles() {
1070                         stylesMemoizer.get();
1071                         return super.getStyles();
1072                 }
1073
1074                 /**
1075                  * {@inheritDoc}
1076                  */
1077                 @Override
1078                 public List<Artist> getRemixArtists() {
1079                         remixArtistsMemoizer.get();
1080                         return super.getRemixArtists();
1081                 }
1082
1083                 /**
1084                  * {@inheritDoc}
1085                  */
1086                 @Override
1087                 public Collection<TrackDerivative> getDerivatives() {
1088                         derivativesMemoizer.get();
1089                         return super.getDerivatives();
1090                 }
1091
1092                 /**
1093                  * {@inheritDoc}
1094                  */
1095                 @Override
1096                 public Map<Relationship, Collection<Track>> getRelatedTracks() {
1097                         relatedTracksMemoizer.get();
1098                         return super.getRelatedTracks();
1099                 }
1100
1101                 /**
1102                  * {@inheritDoc}
1103                  */
1104                 @Override
1105                 public Collection<Party> getParties() {
1106                         if (!hasValue("parties")) {
1107                                 try {
1108                                         getValue("parties", Collection.class).set(getPartiesByTrackId(getId()));
1109                                 } catch (DatabaseException de1) {
1110                                         throw new RuntimeException("Could not load Parties for Track " + getId() + ".", de1);
1111                                 }
1112                         }
1113                         return super.getParties();
1114                 }
1115
1116         }
1117
1118         /**
1119          * {@link ObjectCreator} implementation that can create {@link Track}
1120          * objects. This specific implementation creates {@link LazyTrack}
1121          * instances.
1122          *
1123          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1124          */
1125         private class TrackCreator implements ObjectCreator<Track> {
1126
1127                 /**
1128                  * {@inheritDoc}
1129                  */
1130                 @Override
1131                 public Track createObject(ResultSet resultSet) throws SQLException {
1132                         return new LazyTrack(resultSet.getString("TRACKS.ID")).setName(resultSet.getString("TRACKS.NAME")).setRemix(resultSet.getString("TRACKS.REMIX"));
1133                 }
1134
1135         }
1136
1137         /**
1138          * {@link ObjectCreator} implementation that can create
1139          * {@link TrackDerivative} objects.
1140          *
1141          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1142          */
1143         private class TrackDerivativeCreator implements ObjectCreator<TrackDerivative> {
1144
1145                 /**
1146                  * {@inheritDoc}
1147                  */
1148                 @Override
1149                 public TrackDerivative createObject(ResultSet resultSet) throws SQLException {
1150                         return new DefaultTrackDerivative(resultSet.getString("TRACK_DERIVATIVES.ID"));
1151                 }
1152
1153         }
1154
1155         /**
1156          * {@link ObjectCreator} implementation that can create {@link Style}
1157          * objects.
1158          *
1159          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1160          */
1161         private class StyleCreator implements ObjectCreator<Style> {
1162
1163                 /**
1164                  * {@inheritDoc}
1165                  */
1166                 @Override
1167                 public Style createObject(ResultSet resultSet) throws SQLException {
1168                         return new DefaultStyle(resultSet.getString("STYLES.ID")).setName(resultSet.getString("STYLES.NAME"));
1169                 }
1170
1171         }
1172
1173         /**
1174          * {@link Party} implementation that loads additional information only on
1175          * demand.
1176          *
1177          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1178          */
1179         private class LazyParty extends DefaultParty {
1180
1181                 /**
1182                  * Creates a new party.
1183                  *
1184                  * @param id
1185                  *            The ID of the party
1186                  */
1187                 public LazyParty(String id) {
1188                         super(id);
1189                 }
1190
1191                 //
1192                 // PARTY METHODS
1193                 //
1194
1195                 /**
1196                  * {@inheritDoc}
1197                  */
1198                 @Override
1199                 public Collection<Track> getReleases() {
1200                         if (!hasValue("releases")) {
1201                                 try {
1202                                         getValue("releases", Collection.class).set(getTracksByParty(getId()));
1203                                 } catch (DatabaseException de1) {
1204                                         throw new RuntimeException("Could not loaded Tracks for Party " + getId() + ".", de1);
1205                                 }
1206                         }
1207                         return super.getReleases();
1208                 }
1209
1210         }
1211
1212         /**
1213          * {@link ObjectCreator} implementation that can create {@link Party}
1214          * objects.
1215          *
1216          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1217          */
1218         private class PartyCreator implements ObjectCreator<Party> {
1219
1220                 /**
1221                  * {@inheritDoc}
1222                  */
1223                 @Override
1224                 public Party createObject(ResultSet resultSet) throws SQLException {
1225                         return new LazyParty(resultSet.getString("PARTIES.ID")).setName(resultSet.getString("PARTIES.NAME"));
1226                 }
1227
1228         }
1229
1230         /**
1231          * {@link User} implementation that retrieves some attributes (such as
1232          * {@link #getOpenIds()}) from the {@link DataManager} on demand.
1233          *
1234          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1235          */
1236         private class LazyUser extends DefaultUser {
1237
1238                 /** Memoizer for a user’s OpenIDs. */
1239                 private final Memoizer<Void> openIdMemoizer = new Memoizer<Void>(new Callable<Void>() {
1240
1241                         @Override
1242                         public Void call() throws Exception {
1243                                 if (!hasValue("openIds")) {
1244                                         getValue("openIds", Collection.class).set(getOpenIdsByUser(getId()));
1245                                 }
1246                                 return null;
1247                         }
1248                 });
1249
1250                 /**
1251                  * Creates a new user.
1252                  *
1253                  * @param id
1254                  *            The ID of the user
1255                  */
1256                 public LazyUser(String id) {
1257                         super(id);
1258                 }
1259
1260                 /**
1261                  * {@inheritDoc}
1262                  */
1263                 @Override
1264                 public Collection<String> getOpenIds() {
1265                         openIdMemoizer.get();
1266                         return super.getOpenIds();
1267                 }
1268
1269         }
1270
1271         /**
1272          * {@link ObjectCreator} implementation that can create {@link User}
1273          * objects. This specific implementation creates {@link LazyUser} instances.
1274          *
1275          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1276          */
1277         private class UserCreator implements ObjectCreator<User> {
1278
1279                 /**
1280                  * {@inheritDoc}
1281                  */
1282                 @Override
1283                 public User createObject(ResultSet resultSet) throws SQLException {
1284                         return new LazyUser(resultSet.getString("USERS.ID")).setName(resultSet.getString("USERS.NAME")).setPasswordHash(resultSet.getString("USERS.PASSWORD")).setLevel(resultSet.getInt("USERS.LEVEL"));
1285                 }
1286
1287         }
1288
1289 }