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
 194                 /* save groups. */
 195                 Collection<Group> groups = artist.getGroups();
 196                 query = new Query(Type.DELETE, "GROUP_ARTISTS");
 197                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artist.getId()))));
 198                 database.update(query);
 199                 for (Group group : groups) {
 200                         query = new Query(Type.INSERT, "GROUP_ARTISTS");
 201                         query.addValueField(new ValueField("GROUP_", new StringParameter(group.getId())));
 202                         query.addValueField(new ValueField("ARTIST", new StringParameter(artist.getId())));
 203                         database.insert(query);
 204                 }
 205
 206                 /* save properties. */
 207                 saveArtistProperties(artist);
 208         }
 209
 210         /**
 211          * Saves the properties of the given artist.
 212          *
 213          * @param artist
 214          *            The artist whose properties to save
 215          * @throws DatabaseException
 216          *             if a database error occurs
 217          */
 218         public void saveArtistProperties(Artist artist) throws DatabaseException {
 219                 saveProperties(artist.getProperties(), "ARTIST_PROPERTIES", "ARTIST", artist.getId());
 220         }
 221
 222         /**
 223          * Saves the given properties to the given table for the given principal.
 224          *
 225          * @param properties
 226          *            The properties to save
 227          * @param table
 228          *            The table in which to save the properties
 229          * @param type
 230          *            The type of the principal (e. g. “ARTIST” or “TRACK”)
 231          * @param id
 232          *            The ID of the principial
 233          * @throws DatabaseException
 234          *             if a database error occurs
 235          */
 236         public void saveProperties(Properties properties, String table, String type, String id) throws DatabaseException {
 237                 if (!properties.isDirty()) {
 238                         return;
 239                 }
 240                 Query query = new Query(Type.DELETE, table);
 241                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(id))));
 242                 database.update(query);
 243                 for (Entry<String, String> property : properties) {
 244                         Query insertQuery = new Query(Type.INSERT, table);
 245                         insertQuery.addValueField(new ValueField(type, new StringParameter(id)));
 246                         insertQuery.addValueField(new ValueField("PROPERTY", new StringParameter(property.getKey())));
 247                         insertQuery.addValueField(new ValueField("VALUE", new StringParameter(property.getValue())));
 248                         database.insert(insertQuery);
 249                 }
 250                 properties.resetDirty();
 251         }
 252
 253         /**
 254          * Loads the properties for an artist.
 255          *
 256          * @param artist
 257          *            The artist to load the properties for
 258          * @return The artist
 259          * @throws DatabaseException
 260          *             if a database error occurs
 261          */
 262         public Artist loadArtistProperties(final Artist artist) throws DatabaseException {
 263                 return loadProperties(artist, "ARTIST_PROPERTIES", "ARTIST");
 264         }
 265
 266         /**
 267          * Loads the properties of all given artists.
 268          *
 269          * @param artists
 270          *            The artists to load the properties for
 271          * @return The list of artists
 272          * @throws DatabaseException
 273          *             if a database error occurs
 274          */
 275         public List<Artist> loadArtistProperties(List<Artist> artists) throws DatabaseException {
 276                 for (Artist artist : artists) {
 277                         loadArtistProperties(artist);
 278                 }
 279                 return artists;
 280         }
 281
 282         /**
 283          * Returns all remix artists involved in the track with the given ID.
 284          *
 285          * @param trackId
 286          *            The ID of the track
 287          * @return All remix artists involved in the track, in preferred order
 288          * @throws DatabaseException
 289          *             if a database error occurs
 290          */
 291         public List<Artist> getRemixArtistsByTrack(String trackId) throws DatabaseException {
 292                 Query query = new Query(Type.SELECT, "ARTISTS");
 293                 query.addField(new Field("ARTISTS.*"));
 294                 query.addJoin(new Join(JoinType.INNER, "TRACK_REMIX_ARTISTS", new Field("TRACK_REMIX_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 295                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_REMIX_ARTISTS.TRACK", new StringParameter(trackId))));
 296                 query.addOrderField(new OrderField(new Field("TRACK_REMIX_ARTISTS.DISPLAY_ORDER")));
 297                 return database.getMultiple(query, artistCreator);
 298         }
 299
 300         /**
 301          * Returns all related tracks for the track with the given ID.
 302          *
 303          * @param trackId
 304          *            The ID of the tracks
 305          * @return A mapping from relationship to all tracks that match the relation
 306          * @throws DatabaseException
 307          *             if a database error occurs
 308          */
 309         public Map<Relationship, Collection<Track>> getRelatedTracksByTrack(String trackId) throws DatabaseException {
 310                 Query query = new Query(Type.SELECT, "TRACKS");
 311                 query.addField(new Field("TRACKS.*"));
 312                 query.addField(new Field("TRACK_RELATIONS.*"));
 313                 query.addJoin(new Join(JoinType.INNER, "TRACK_RELATIONS", new Field("TRACK_RELATIONS.TRACK"), new Field("TRACK_RELATIONS.RELATED_TRACK")));
 314                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_RELATIONS.TRACK", new StringParameter(trackId))));
 315                 final Map<Relationship, Collection<Track>> relatedTracks = new EnumMap<Relationship, Collection<Track>>(Relationship.class);
 316                 database.process(query, new ResultProcessor() {
 317
 318                         @Override
 319                         @SuppressWarnings("synthetic-access")
 320                         public void processResult(ResultSet resultSet) throws SQLException {
 321                                 Track track = trackCreator.createObject(resultSet);
 322                                 Relationship relationship = Relationship.valueOf(resultSet.getString("TRACK_RELATIONS.RELATIONSHIP"));
 323                                 if (!relatedTracks.containsKey(relationship)) {
 324                                         relatedTracks.put(relationship, new HashSet<Track>());
 325                                 }
 326                                 relatedTracks.get(relationship).add(track);
 327                         }
 328                 });
 329                 return relatedTracks;
 330         }
 331
 332         /**
 333          * Returns the track with the given ID.
 334          *
 335          * @param id
 336          *            The ID of the track
 337          * @return The track with the given ID, or {@code null} if there is no such
 338          *         track
 339          * @throws DatabaseException
 340          *             if a database error occurs
 341          */
 342         public Track getTrackById(String id) throws DatabaseException {
 343                 Query query = new Query(Type.SELECT, "TRACKS");
 344                 query.addField(new Field("TRACKS.*"));
 345                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(id))));
 346                 return loadTrackProperties(database.getSingle(query, trackCreator));
 347         }
 348
 349         /**
 350          * Returns the track that contains the derivative with the given ID.
 351          *
 352          * @param id
 353          *            The ID of the track derivative
 354          * @return The track the derivative belongs to, or {@code null} if there is
 355          *         no such track
 356          * @throws DatabaseException
 357          *             if a database error occurs
 358          */
 359         public Track getTrackByDerivativeId(String id) throws DatabaseException {
 360                 Query query = new Query(Type.SELECT, "TRACKS");
 361                 query.addField(new Field("TRACKS.*"));
 362                 query.addJoin(new Join(JoinType.INNER, "TRACK_DERIVATIVES", new Field("TRACK_DERIVATIVES.TRACK"), new Field("TRACKS.ID")));
 363                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id))));
 364                 return loadTrackProperties(database.getSingle(query, trackCreator));
 365         }
 366
 367         /**
 368          * Returns all tracks by the artist with the given ID.
 369          *
 370          * @param artistId
 371          *            The ID of the artist
 372          * @return All tracks by the given artist
 373          * @throws DatabaseException
 374          *             if a database error occurs
 375          */
 376         public Collection<Track> getTracksByArtist(String artistId) throws DatabaseException {
 377                 Query query = new Query(Type.SELECT, "TRACKS");
 378                 query.addField(new Field("TRACKS.*"));
 379                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACKS.ID"), new Field("TRACK_ARTISTS.TRACK")));
 380                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(artistId))));
 381                 return loadTrackProperties(database.getMultiple(query, trackCreator));
 382         }
 383
 384         /**
 385          * Returns all tracks that were released at the party with the given ID.
 386          *
 387          * @param partyId
 388          *            The ID of the party
 389          * @return All tracks that were released at the given party
 390          * @throws DatabaseException
 391          *             if a database error occurs
 392          */
 393         public Collection<Track> getTracksByParty(String partyId) throws DatabaseException {
 394                 Query query = new Query(Type.SELECT, "TRACKS");
 395                 query.addField(new Field("TRACKS.*"));
 396                 query.addJoin(new Join(JoinType.INNER, "PARTY_TRACKS", new Field("PARTY_TRACKS.TRACK"), new Field("TRACKS.ID")));
 397                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTY_TRACKS.PARTY", new StringParameter(partyId))));
 398                 return loadTrackProperties(database.getMultiple(query, trackCreator));
 399         }
 400
 401         /**
 402          * Loads the properties for the given track.
 403          *
 404          * @param track
 405          *            The track for which to load the properties
 406          * @return The track with the properties loaded
 407          * @throws DatabaseException
 408          *             if a database error occurs
 409          */
 410         public Track loadTrackProperties(Track track) throws DatabaseException {
 411                 return loadProperties(track, "TRACK_PROPERTIES", "TRACK");
 412         }
 413
 414         /**
 415          * Loads the properties for the given tracks.
 416          *
 417          * @param tracks
 418          *            The tracks for which to load the properties
 419          * @return The tracks with the properties loaded
 420          * @throws DatabaseException
 421          *             if a database error occurs
 422          */
 423         public List<Track> loadTrackProperties(List<Track> tracks) throws DatabaseException {
 424                 for (Track track : tracks) {
 425                         loadTrackProperties(track);
 426                 }
 427                 return tracks;
 428         }
 429
 430         /**
 431          * Creates a new track with the given name.
 432          *
 433          * @param name
 434          *            The name of the track
 435          * @return The created track
 436          * @throws DatabaseException
 437          *             if a database error occurs
 438          */
 439         public Track createTrack(String name) throws DatabaseException {
 440                 Query query = new Query(Type.INSERT, "TRACKS");
 441                 String id = UUID.randomUUID().toString();
 442                 query.addValueField(new ValueField("ID", new StringParameter(id)));
 443                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
 444                 database.insert(query);
 445                 return getTrackById(id);
 446         }
 447
 448         /**
 449          * Saves the given track. This also saves all relationships of the track.
 450          *
 451          * @param track
 452          *            The track to save
 453          * @throws DatabaseException
 454          *             if a database error occurs
 455          */
 456         public void saveTrack(Track track) throws DatabaseException {
 457                 Query query = new Query(Type.UPDATE, "TRACKS");
 458                 query.addValueField(new ValueField("TRACKS.NAME", new StringParameter(track.getName())));
 459                 query.addValueField(new ValueField("TRACKS.REMIX", new StringParameter(track.getRemix())));
 460                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(track.getId()))));
 461                 database.update(query);
 462                 /* store artist information. */
 463                 track.getArtists(); /* prefetch artists. */
 464                 query = new Query(Type.DELETE, "TRACK_ARTISTS");
 465                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(track.getId()))));
 466                 database.update(query);
 467                 for (int index = 0; index < track.getArtists().size(); ++index) {
 468                         query = new Query(Type.INSERT, "TRACK_ARTISTS");
 469                         query.addValueField(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(track.getId())));
 470                         query.addValueField(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(track.getArtists().get(index).getId())));
 471                         query.addValueField(new ValueField("TRACK_ARTISTS.DISPLAY_ORDER", new IntegerParameter(index + 1)));
 472                         database.insert(query);
 473                 }
 474
 475                 /* store party links. */
 476                 Collection<Party> parties = track.getParties(); /* prefetch parties. */
 477                 query = new Query(Type.DELETE, "PARTY_TRACKS");
 478                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTY_TRACKS.TRACK", new StringParameter(track.getId()))));
 479                 database.update(query);
 480                 for (Party party : parties) {
 481                         query = new Query(Type.INSERT, "PARTY_TRACKS");
 482                         query.addValueField(new ValueField("PARTY_TRACKS.TRACK", new StringParameter(track.getId())));
 483                         query.addValueField(new ValueField("PARTY_TRACKS.PARTY", new StringParameter(party.getId())));
 484                         database.insert(query);
 485                 }
 486
 487                 /* store properties. */
 488                 saveProperties(track.getProperties(), "TRACK_PROPERTIES", "TRACK", track.getId());
 489         }
 490
 491         /**
 492          * Returns the derivative with the given ID.
 493          *
 494          * @param id
 495          *            The ID of the derivatives to load
 496          * @return The derivative with the given ID
 497          * @throws DatabaseException
 498          *             if a database error occurs
 499          */
 500         public TrackDerivative getTrackDerivativeById(String id) throws DatabaseException {
 501                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 502                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 503                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id))));
 504                 return loadTrackDerivativeProperties(database.getSingle(query, trackDerivativeCreator));
 505         }
 506
 507         /**
 508          * Returns the derivatives for the given track.
 509          *
 510          * @param trackId
 511          *            The track ID to get the derivatives for
 512          * @return The derivatives for the given track
 513          * @throws DatabaseException
 514          *             if a database error occurs
 515          */
 516         public Collection<TrackDerivative> getTrackDerivativesByTrack(String trackId) throws DatabaseException {
 517                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 518                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 519                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(trackId))));
 520                 return loadTrackDerivativeProperties(database.getMultiple(query, trackDerivativeCreator));
 521         }
 522
 523         /**
 524          * Creates a new derivative for the given track.
 525          *
 526          * @param track
 527          *            The track to create the derivative for
 528          * @return The created derivative
 529          * @throws DatabaseException
 530          *             if a database error occurs
 531          */
 532         public TrackDerivative createTrackDerivative(Track track) throws DatabaseException {
 533                 Query query = new Query(Type.INSERT, "TRACK_DERIVATIVES");
 534                 String id = UUID.randomUUID().toString();
 535                 query.addValueField(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id)));
 536                 query.addValueField(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(track.getId())));
 537                 database.insert(query);
 538                 return getTrackDerivativeById(id);
 539         }
 540
 541         /**
 542          * Loads the properties for the given track derivative.
 543          *
 544          * @param trackDerivative
 545          *            The track derivative to load the properties for
 546          * @return The track derivative with its properties loaded
 547          * @throws DatabaseException
 548          *             if a database error occurs
 549          */
 550         public TrackDerivative loadTrackDerivativeProperties(TrackDerivative trackDerivative) throws DatabaseException {
 551                 return loadProperties(trackDerivative, "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE");
 552         }
 553
 554         /**
 555          * Loads the properties for the given track derivatives.
 556          *
 557          * @param trackDerivatives
 558          *            The track derivatives to load the properties for
 559          * @return The track derivatives with their properties loaded
 560          * @throws DatabaseException
 561          *             if a database error occurs
 562          */
 563         public List<TrackDerivative> loadTrackDerivativeProperties(List<TrackDerivative> trackDerivatives) throws DatabaseException {
 564                 for (TrackDerivative trackDerivative : trackDerivatives) {
 565                         loadTrackDerivativeProperties(trackDerivative);
 566                 }
 567                 return trackDerivatives;
 568         }
 569
 570         /**
 571          * Saves the given track derivative. As a track derivative does not have any
 572          * attributes of its own only its properties are saved.
 573          *
 574          * @param trackDerivative
 575          *            The track derivative to save
 576          * @throws DatabaseException
 577          *             if a database error occurs
 578          */
 579         public void saveTrackDerivate(TrackDerivative trackDerivative) throws DatabaseException {
 580                 saveProperties(trackDerivative.getProperties(), "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE", trackDerivative.getId());
 581         }
 582
 583         /**
 584          * Removes the given track derivative and all its properties from the
 585          * database.
 586          *
 587          * @param trackDerivative
 588          *            The track derivative to remove
 589          * @throws DatabaseException
 590          *             if a database error occurs
 591          */
 592         public void removeTrackDerivative(TrackDerivative trackDerivative) throws DatabaseException {
 593                 Query query = new Query(Type.DELETE, "TRACK_DERIVATIVES");
 594                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(trackDerivative.getId()))));
 595                 database.update(query);
 596                 /* remove the properties. */
 597                 saveProperties(new Properties().set("dirty", "true").removeAll(), "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE", trackDerivative.getId());
 598         }
 599
 600         /**
 601          * Returns all groups the artist with the given ID belongs to.
 602          *
 603          * @param artistId
 604          *            The ID of the artist
 605          * @return All groups the artist belongs to
 606          * @throws DatabaseException
 607          *             if a database error occurs
 608          */
 609         public Collection<Group> getGroupsByArtist(String artistId) throws DatabaseException {
 610                 Query query = new Query(Type.SELECT, "GROUPS");
 611                 query.addField(new Field("GROUPS.*"));
 612                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("GROUPS.ID"), new Field("GROUP_ARTISTS.GROUP_")));
 613                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artistId))));
 614                 return database.getMultiple(query, groupCreator);
 615         }
 616
 617         /**
 618          * Returns all styles for the track with the given ID.
 619          *
 620          * @param trackId
 621          *            The ID of the track
 622          * @return All styles for the given track
 623          * @throws DatabaseException
 624          *             if a database error occurs
 625          */
 626         public Collection<Style> getStylesByTrack(String trackId) throws DatabaseException {
 627                 Query query = new Query(Type.SELECT, "STYLES");
 628                 query.addField(new Field("STYLES.*"));
 629                 query.addJoin(new Join(JoinType.INNER, "TRACK_STYLES", new Field("STYLES.ID"), new Field("TRACK_STYLES.STYLE")));
 630                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_STYLES.TRACK", new StringParameter(trackId))));
 631                 return database.getMultiple(query, styleCreator);
 632         }
 633
 634         /**
 635          * Returns all parties.
 636          *
 637          * @return All parties
 638          * @throws DatabaseException
 639          *             if a database error occurs
 640          */
 641         public Collection<Party> getAllParties() throws DatabaseException {
 642                 Query query = new Query(Type.SELECT, "PARTIES");
 643                 query.addField(new Field("PARTIES.*"));
 644                 return loadPartyProperties(database.getMultiple(query, partyCreator));
 645         }
 646
 647         /**
 648          * Returns all parties that the track with the given ID was released at.
 649          *
 650          * @param trackId
 651          *            The ID of the track
 652          * @return All parties the track was released at
 653          * @throws DatabaseException
 654          *             if a database error occurs
 655          */
 656         public Collection<Party> getPartiesByTrackId(String trackId) throws DatabaseException {
 657                 Query query = new Query(Type.SELECT, "PARTIES");
 658                 query.addField(new Field("PARTIES.*"));
 659                 query.addJoin(new Join(JoinType.INNER, "PARTY_TRACKS", new Field("PARTY_TRACKS.PARTY"), new Field("PARTIES.ID")));
 660                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTY_TRACKS.TRACK", new StringParameter(trackId))));
 661                 return loadPartyProperties(database.getMultiple(query, partyCreator));
 662         }
 663
 664         /**
 665          * Returns the party with the given ID.
 666          *
 667          * @param partyId
 668          *            The ID of the party
 669          * @return The party with the given ID
 670          * @throws DatabaseException
 671          *             if a database error occurs
 672          */
 673         public Party getPartyById(String partyId) throws DatabaseException {
 674                 Query query = new Query(Type.SELECT, "PARTIES");
 675                 query.addField(new Field("PARTIES.*"));
 676                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTIES.ID", new StringParameter(partyId))));
 677                 return loadPartyProperties(database.getSingle(query, partyCreator));
 678         }
 679
 680         /**
 681          * Loads the properties of the given party.
 682          *
 683          * @param party
 684          *            The party to load the properties for
 685          * @return The party with its properties loaded
 686          * @throws DatabaseException
 687          *             if a database error occurs
 688          */
 689         public Party loadPartyProperties(Party party) throws DatabaseException {
 690                 return loadProperties(party, "PARTY_PROPERTIES", "PARTY");
 691         }
 692
 693         /**
 694          * Loads the properties of the given parties.
 695          *
 696          * @param parties
 697          *            The parties to load the properties for
 698          * @return The parties with their properties loaded
 699          * @throws DatabaseException
 700          *             if a database error occurs
 701          */
 702         public List<Party> loadPartyProperties(List<Party> parties) throws DatabaseException {
 703                 for (Party party : parties) {
 704                         loadPartyProperties(party);
 705                 }
 706                 return parties;
 707         }
 708
 709         /**
 710          * Saves the given party.
 711          *
 712          * @param party
 713          *            The party to save
 714          * @throws DatabaseException
 715          *             if a database error occurs
 716          */
 717         public void saveParty(Party party) throws DatabaseException {
 718                 Query query = new Query(Type.UPDATE, "PARTIES");
 719                 query.addValueField(new ValueField("NAME", new StringParameter(party.getName())));
 720                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ID", new StringParameter(party.getId()))));
 721                 database.update(query);
 722                 savePartyProperties(party);
 723         }
 724
 725         /**
 726          * Saves the properties of the given party.
 727          *
 728          * @param party
 729          *            The party whose properties to save
 730          * @throws DatabaseException
 731          *             if a database error occurs
 732          */
 733         public void savePartyProperties(Party party) throws DatabaseException {
 734                 saveProperties(party.getProperties(), "PARTY_PROPERTIES", "PARTY", party.getId());
 735         }
 736
 737         /**
 738          * Creates a new party with the given name.
 739          *
 740          * @param name
 741          *            The name of the party
 742          * @return The new party
 743          * @throws DatabaseException
 744          *             if a database error occurs
 745          */
 746         public Party createParty(String name) throws DatabaseException {
 747                 Query query = new Query(Type.INSERT, "PARTIES");
 748                 String id = UUID.randomUUID().toString();
 749                 query.addValueField(new ValueField("ID", new StringParameter(id)));
 750                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
 751                 database.insert(query);
 752                 return getPartyById(id);
 753         }
 754
 755         /**
 756          * Returns the user with the given name.
 757          *
 758          * @param username
 759          *            The name of the user
 760          * @return The user, or {@code null} if the user does not exist
 761          * @throws DatabaseException
 762          *             if a database error occurs
 763          */
 764         public User getUserByName(String username) throws DatabaseException {
 765                 Query query = new Query(Type.SELECT, "USERS");
 766                 query.addField(new Field("USERS.*"));
 767                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USERS.NAME", new StringParameter(username))));
 768                 return database.getSingle(query, userCreator);
 769         }
 770
 771         /**
 772          * Returns the user connected with the given OpenID.
 773          *
 774          * @param openId
 775          *            The OpenID to find the user for
 776          * @return The user connected with the given OpenID, or {@code null} if
 777          *         there is no such user
 778          * @throws DatabaseException
 779          *             if a database error occurs
 780          */
 781         public User getUserByOpenId(String openId) throws DatabaseException {
 782                 Query query = new Query(Type.SELECT, "USERS");
 783                 query.addField(new Field("USERS.*"));
 784                 query.addJoin(new Join(JoinType.INNER, "USER_OPENIDS", new Field("USER_OPENIDS.USER"), new Field("USERS.ID")));
 785                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.OPENID", new StringParameter(openId))));
 786                 return database.getSingle(query, userCreator);
 787         }
 788
 789         /**
 790          * Returns all OpenIDs connected with the user with the given ID.
 791          *
 792          * @param userId
 793          *            The ID of the user
 794          * @return All OpenIDs connected with the given user
 795          * @throws DatabaseException
 796          *             if a database error occurs
 797          */
 798         public Collection<String> getOpenIdsByUser(String userId) throws DatabaseException {
 799                 Query query = new Query(Type.SELECT, "USER_OPENIDS");
 800                 query.addField(new Field("USER_OPENIDS.*"));
 801                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.USER", new StringParameter(userId))));
 802                 return database.getMultiple(query, new StringCreator("USER_OPENIDS.OPENID"));
 803         }
 804
 805         //
 806         // PRIVATE METHODS
 807         //
 808
 809         /**
 810          * Loads the properties for the given object.
 811          *
 812          * @param <T>
 813          *            The type of the object
 814          * @param object
 815          *            The object
 816          * @param table
 817          *            The table to load the properties from
 818          * @param type
 819          *            The type of the object (“ARTIST,” “TRACK,” etc.)
 820          * @return The object with its properties loaded
 821          * @throws DatabaseException
 822          *             if a database error occurs
 823          */
 824         private <T extends Base> T loadProperties(final T object, final String table, String type) throws DatabaseException {
 825                 if (object == null) {
 826                         return null;
 827                 }
 828                 Query query = new Query(Type.SELECT, table);
 829                 query.addField(new Field(table + ".PROPERTY"));
 830                 query.addField(new Field(table + ".VALUE"));
 831                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(object.getId()))));
 832                 database.process(query, new ResultProcessor() {
 833
 834                         @Override
 835                         public void processResult(ResultSet resultSet) throws SQLException {
 836                                 if (resultSet.isFirst()) {
 837                                         object.getProperties().removeAll();
 838                                 }
 839                                 object.getProperties().set(resultSet.getString(table + ".PROPERTY"), resultSet.getString(table + ".VALUE"));
 840                         }
 841
 842                 });
 843                 return object;
 844         }
 845
 846         /**
 847          * {@link Artist} implementation that retrieves some attributes (such as
 848          * {@link #getGroups()}, and {@link #getTracks()}) from the
 849          * {@link DataManager} on demand.
 850          *
 851          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 852          */
 853         private class LazyArtist extends DefaultArtist {
 854
 855                 /** Memoizer for the tracks by this artist. */
 856                 private final Memoizer<Void> tracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 857
 858                         @Override
 859                         public Void call() throws DatabaseException {
 860                                 if (!hasValue("tracks")) {
 861                                         getValue("tracks", Collection.class).set(getTracksByArtist(getId()));
 862                                 }
 863                                 return null;
 864                         }
 865                 });
 866
 867                 /** Memoizer for the groups of this artist. */
 868                 private final Memoizer<Void> groupsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 869
 870                         @Override
 871                         public Void call() throws Exception {
 872                                 if (!hasValue("groups")) {
 873                                         getValue("groups", Collection.class).set(getGroupsByArtist(getId()));
 874                                 }
 875                                 return null;
 876                         }
 877
 878                 });
 879
 880                 /**
 881                  * Creates a new lazy artist.
 882                  *
 883                  * @param id
 884                  *            The ID of the artist
 885                  */
 886                 public LazyArtist(String id) {
 887                         super(id);
 888                 }
 889
 890                 //
 891                 // DEFAULTARTIST METHODS
 892                 //
 893
 894                 /**
 895                  * {@inheritDoc}
 896                  */
 897                 @Override
 898                 public Collection<Group> getGroups() {
 899                         groupsMemoizer.get();
 900                         return super.getGroups();
 901                 }
 902
 903                 /**
 904                  * {@inheritDoc}
 905                  */
 906                 @Override
 907                 public Collection<Track> getTracks() {
 908                         tracksMemoizer.get();
 909                         return super.getTracks();
 910                 }
 911
 912         }
 913
 914         /**
 915          * {@link ObjectCreator} implementation that can create {@link Artist}
 916          * objects. This specific class actually creates {@link LazyArtist}
 917          * instances.
 918          *
 919          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 920          */
 921         private class ArtistCreator implements ObjectCreator<Artist> {
 922
 923                 /**
 924                  * {@inheritDoc}
 925                  */
 926                 @Override
 927                 public Artist createObject(ResultSet resultSet) throws SQLException {
 928                         return new LazyArtist(resultSet.getString("ARTISTS.ID")).setName(resultSet.getString("ARTISTS.NAME"));
 929                 }
 930
 931         }
 932
 933         /**
 934          * {@link Group} implementation that retrieves some attributes (such as
 935          * {@link #getArtists()}) from the {@link DataManager} on demand.
 936          *
 937          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 938          */
 939         private class LazyGroup extends DefaultGroup {
 940
 941                 /** Memoizer for the artist. */
 942                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 943
 944                         @Override
 945                         public Void call() throws Exception {
 946                                 if (!hasValue("artists")) {
 947                                         getValue("artists", Collection.class).set(getArtistsByGroup(getId()));
 948                                 }
 949                                 return null;
 950                         }
 951
 952                 });
 953
 954                 /**
 955                  * Creates a new lazy group.
 956                  *
 957                  * @param id
 958                  *            The ID of the group
 959                  */
 960                 public LazyGroup(String id) {
 961                         super(id);
 962                 }
 963
 964                 //
 965                 // DEFAULTGROUP METHODS
 966                 //
 967
 968                 /**
 969                  * {@inheritDoc}
 970                  */
 971                 @Override
 972                 public Collection<Artist> getArtists() {
 973                         artistsMemoizer.get();
 974                         return super.getArtists();
 975                 }
 976
 977         }
 978
 979         /**
 980          * {@link ObjectCreator} implementation that can create {@link Group}
 981          * objects. This specific implementation creates {@link LazyGroup}
 982          * instances.
 983          *
 984          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 985          */
 986         private class GroupCreator implements ObjectCreator<Group> {
 987
 988                 /**
 989                  * {@inheritDoc}
 990                  */
 991                 @Override
 992                 public Group createObject(ResultSet resultSet) throws SQLException {
 993                         return new LazyGroup(resultSet.getString("GROUPS.ID")).setName(resultSet.getString("GROUPS.NAME")).setUrl(resultSet.getString("GROUPS.URL"));
 994                 }
 995
 996         }
 997
 998         /**
 999          * {@link Track} implementation that retrieves some attributes (such as
1000          * {@link #getArtists()}, and {@link #getStyles()}) from the
1001          * {@link DataManager} on demand.
1002          *
1003          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1004          */
1005         private class LazyTrack extends DefaultTrack {
1006
1007                 /** Memoizer for the artists. */
1008                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
1009
1010                         @Override
1011                         public Void call() throws Exception {
1012                                 if (!hasValue("artists")) {
1013                                         getValue("artists", List.class).set(getArtistsByTrack(getId()));
1014                                 }
1015                                 return null;
1016                         }
1017
1018                 });
1019
1020                 /** Memoizer for the styles. */
1021                 private final Memoizer<Void> stylesMemoizer = new Memoizer<Void>(new Callable<Void>() {
1022
1023                         @Override
1024                         public Void call() throws Exception {
1025                                 if (!hasValue("styles")) {
1026                                         getValue("styles", Collection.class).set(getStylesByTrack(getId()));
1027                                 }
1028                                 return null;
1029                         }
1030
1031                 });
1032
1033                 /** Memoizer for the remix artists. */
1034                 private final Memoizer<Void> remixArtistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
1035
1036                         @Override
1037                         public Void call() throws Exception {
1038                                 if (!hasValue("remixArtists")) {
1039                                         getValue("remixArtists", List.class).set(getRemixArtistsByTrack(getId()));
1040                                 }
1041                                 return null;
1042                         }
1043
1044                 });
1045
1046                 /** Memoizer for the track derivatives. */
1047                 private final Memoizer<Void> derivativesMemoizer = new Memoizer<Void>(new Callable<Void>() {
1048
1049                         @Override
1050                         public Void call() throws Exception {
1051                                 if (!hasValue("derivatives")) {
1052                                         getValue("derivatives", Collection.class).set(getTrackDerivativesByTrack(getId()));
1053                                 }
1054                                 return null;
1055                         }
1056
1057                 });
1058
1059                 /** Memoizer for the related tracks. */
1060                 private final Memoizer<Void> relatedTracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
1061
1062                         @Override
1063                         public Void call() throws Exception {
1064                                 if (!hasValue("relatedTracks")) {
1065                                         getValue("relatedTracks", Map.class).set(getRelatedTracksByTrack(getId()));
1066                                 }
1067                                 return null;
1068                         }
1069
1070                 });
1071
1072                 /**
1073                  * Creates a new track.
1074                  *
1075                  * @param id
1076                  *            The ID of the track
1077                  */
1078                 public LazyTrack(String id) {
1079                         super(id);
1080                 }
1081
1082                 //
1083                 // DEFAULTTRACK METHODS
1084                 //
1085
1086                 /**
1087                  * {@inheritDoc}
1088                  */
1089                 @Override
1090                 public List<Artist> getArtists() {
1091                         artistsMemoizer.get();
1092                         return super.getArtists();
1093                 }
1094
1095                 /**
1096                  * {@inheritDoc}
1097                  */
1098                 @Override
1099                 public Collection<Style> getStyles() {
1100                         stylesMemoizer.get();
1101                         return super.getStyles();
1102                 }
1103
1104                 /**
1105                  * {@inheritDoc}
1106                  */
1107                 @Override
1108                 public List<Artist> getRemixArtists() {
1109                         remixArtistsMemoizer.get();
1110                         return super.getRemixArtists();
1111                 }
1112
1113                 /**
1114                  * {@inheritDoc}
1115                  */
1116                 @Override
1117                 public Collection<TrackDerivative> getDerivatives() {
1118                         derivativesMemoizer.get();
1119                         return super.getDerivatives();
1120                 }
1121
1122                 /**
1123                  * {@inheritDoc}
1124                  */
1125                 @Override
1126                 public Map<Relationship, Collection<Track>> getRelatedTracks() {
1127                         relatedTracksMemoizer.get();
1128                         return super.getRelatedTracks();
1129                 }
1130
1131                 /**
1132                  * {@inheritDoc}
1133                  */
1134                 @Override
1135                 public Collection<Party> getParties() {
1136                         if (!hasValue("parties")) {
1137                                 try {
1138                                         getValue("parties", Collection.class).set(getPartiesByTrackId(getId()));
1139                                 } catch (DatabaseException de1) {
1140                                         throw new RuntimeException("Could not load Parties for Track " + getId() + ".", de1);
1141                                 }
1142                         }
1143                         return super.getParties();
1144                 }
1145
1146         }
1147
1148         /**
1149          * {@link ObjectCreator} implementation that can create {@link Track}
1150          * objects. This specific implementation creates {@link LazyTrack}
1151          * instances.
1152          *
1153          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1154          */
1155         private class TrackCreator implements ObjectCreator<Track> {
1156
1157                 /**
1158                  * {@inheritDoc}
1159                  */
1160                 @Override
1161                 public Track createObject(ResultSet resultSet) throws SQLException {
1162                         return new LazyTrack(resultSet.getString("TRACKS.ID")).setName(resultSet.getString("TRACKS.NAME")).setRemix(resultSet.getString("TRACKS.REMIX"));
1163                 }
1164
1165         }
1166
1167         /**
1168          * {@link ObjectCreator} implementation that can create
1169          * {@link TrackDerivative} objects.
1170          *
1171          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1172          */
1173         private class TrackDerivativeCreator implements ObjectCreator<TrackDerivative> {
1174
1175                 /**
1176                  * {@inheritDoc}
1177                  */
1178                 @Override
1179                 public TrackDerivative createObject(ResultSet resultSet) throws SQLException {
1180                         return new DefaultTrackDerivative(resultSet.getString("TRACK_DERIVATIVES.ID"));
1181                 }
1182
1183         }
1184
1185         /**
1186          * {@link ObjectCreator} implementation that can create {@link Style}
1187          * objects.
1188          *
1189          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1190          */
1191         private class StyleCreator implements ObjectCreator<Style> {
1192
1193                 /**
1194                  * {@inheritDoc}
1195                  */
1196                 @Override
1197                 public Style createObject(ResultSet resultSet) throws SQLException {
1198                         return new DefaultStyle(resultSet.getString("STYLES.ID")).setName(resultSet.getString("STYLES.NAME"));
1199                 }
1200
1201         }
1202
1203         /**
1204          * {@link Party} implementation that loads additional information only on
1205          * demand.
1206          *
1207          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1208          */
1209         private class LazyParty extends DefaultParty {
1210
1211                 /**
1212                  * Creates a new party.
1213                  *
1214                  * @param id
1215                  *            The ID of the party
1216                  */
1217                 public LazyParty(String id) {
1218                         super(id);
1219                 }
1220
1221                 //
1222                 // PARTY METHODS
1223                 //
1224
1225                 /**
1226                  * {@inheritDoc}
1227                  */
1228                 @Override
1229                 public Collection<Track> getReleases() {
1230                         if (!hasValue("releases")) {
1231                                 try {
1232                                         getValue("releases", Collection.class).set(getTracksByParty(getId()));
1233                                 } catch (DatabaseException de1) {
1234                                         throw new RuntimeException("Could not loaded Tracks for Party " + getId() + ".", de1);
1235                                 }
1236                         }
1237                         return super.getReleases();
1238                 }
1239
1240         }
1241
1242         /**
1243          * {@link ObjectCreator} implementation that can create {@link Party}
1244          * objects.
1245          *
1246          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1247          */
1248         private class PartyCreator implements ObjectCreator<Party> {
1249
1250                 /**
1251                  * {@inheritDoc}
1252                  */
1253                 @Override
1254                 public Party createObject(ResultSet resultSet) throws SQLException {
1255                         return new LazyParty(resultSet.getString("PARTIES.ID")).setName(resultSet.getString("PARTIES.NAME"));
1256                 }
1257
1258         }
1259
1260         /**
1261          * {@link User} implementation that retrieves some attributes (such as
1262          * {@link #getOpenIds()}) from the {@link DataManager} on demand.
1263          *
1264          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1265          */
1266         private class LazyUser extends DefaultUser {
1267
1268                 /** Memoizer for a user’s OpenIDs. */
1269                 private final Memoizer<Void> openIdMemoizer = new Memoizer<Void>(new Callable<Void>() {
1270
1271                         @Override
1272                         public Void call() throws Exception {
1273                                 if (!hasValue("openIds")) {
1274                                         getValue("openIds", Collection.class).set(getOpenIdsByUser(getId()));
1275                                 }
1276                                 return null;
1277                         }
1278                 });
1279
1280                 /**
1281                  * Creates a new user.
1282                  *
1283                  * @param id
1284                  *            The ID of the user
1285                  */
1286                 public LazyUser(String id) {
1287                         super(id);
1288                 }
1289
1290                 /**
1291                  * {@inheritDoc}
1292                  */
1293                 @Override
1294                 public Collection<String> getOpenIds() {
1295                         openIdMemoizer.get();
1296                         return super.getOpenIds();
1297                 }
1298
1299         }
1300
1301         /**
1302          * {@link ObjectCreator} implementation that can create {@link User}
1303          * objects. This specific implementation creates {@link LazyUser} instances.
1304          *
1305          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1306          */
1307         private class UserCreator implements ObjectCreator<User> {
1308
1309                 /**
1310                  * {@inheritDoc}
1311                  */
1312                 @Override
1313                 public User createObject(ResultSet resultSet) throws SQLException {
1314                         return new LazyUser(resultSet.getString("USERS.ID")).setName(resultSet.getString("USERS.NAME")).setPasswordHash(resultSet.getString("USERS.PASSWORD")).setLevel(resultSet.getInt("USERS.LEVEL"));
1315                 }
1316
1317         }
1318
1319 }