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.StringParameter;
  42 import net.pterodactylus.util.database.Query;
  43 import net.pterodactylus.util.database.Query.Type;
  44 import net.pterodactylus.util.database.ResultProcessor;
  45 import net.pterodactylus.util.database.ValueField;
  46 import net.pterodactylus.util.database.ValueFieldWhereClause;
  47
  48 /**
  49  * Interface between the database and the application.
  50  *
  51  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  52  */
  53 public class DataManager {
  54
  55         /** The artist object creator. */
  56         @SuppressWarnings("synthetic-access")
  57         private final ObjectCreator<Artist> artistCreator = new ArtistCreator();
  58
  59         /** The group object creator. */
  60         @SuppressWarnings("synthetic-access")
  61         private final ObjectCreator<Group> groupCreator = new GroupCreator();
  62
  63         /** The track object creator. */
  64         @SuppressWarnings("synthetic-access")
  65         private final ObjectCreator<Track> trackCreator = new TrackCreator();
  66
  67         /** The track object creator. */
  68         @SuppressWarnings("synthetic-access")
  69         private final ObjectCreator<TrackDerivative> trackDerivativeCreator = new TrackDerivativeCreator();
  70
  71         /** The style object creator. */
  72         @SuppressWarnings("synthetic-access")
  73         private final ObjectCreator<Style> styleCreator = new StyleCreator();
  74
  75         /** The {@link User} object creator. */
  76         @SuppressWarnings("synthetic-access")
  77         private final ObjectCreator<User> userCreator = new UserCreator();
  78
  79         /** The database. */
  80         private final Database database;
  81
  82         /**
  83          * Creates a new data manager.
  84          *
  85          * @param database
  86          *            The database to operate on
  87          */
  88         public DataManager(Database database) {
  89                 this.database = database;
  90         }
  91
  92         /**
  93          * Returns all artists.
  94          *
  95          * @return All artists
  96          * @throws DatabaseException
  97          *             if a database error occurs
  98          */
  99         public Collection<Artist> getAllArtists() throws DatabaseException {
 100                 Query query = new Query(Type.SELECT, "ARTISTS");
 101                 query.addField(new Field("ARTISTS.*"));
 102                 return loadArtistProperties(database.getMultiple(query, artistCreator));
 103         }
 104
 105         /**
 106          * Returns the artist with the given ID.
 107          *
 108          * @param id
 109          *            The ID of the artist
 110          * @return The artist with the given ID, or {@code null} if there is no
 111          *         artist with the given ID
 112          * @throws DatabaseException
 113          *             if a database error occurs
 114          */
 115         public Artist getArtistById(String id) throws DatabaseException {
 116                 Query query = new Query(Type.SELECT, "ARTISTS");
 117                 query.addField(new Field("ARTISTS.*"));
 118                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ARTISTS.ID", new StringParameter(id))));
 119                 return loadArtistProperties(database.getSingle(query, artistCreator));
 120         }
 121
 122         /**
 123          * Returns all artists that belong to the group with the given ID.
 124          *
 125          * @param groupId
 126          *            The ID of the group
 127          * @return All artists belonging to the given group
 128          * @throws DatabaseException
 129          *             if a database error occurs
 130          */
 131         public Collection<Artist> getArtistsByGroup(String groupId) throws DatabaseException {
 132                 Query query = new Query(Type.SELECT, "ARTISTS");
 133                 query.addField(new Field("ARTISTS.*"));
 134                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("ARTISTS.ID"), new Field("GROUP_ARTISTS.ARTIST")));
 135                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.GROUP_", new StringParameter(groupId))));
 136                 return loadArtistProperties(database.getMultiple(query, artistCreator));
 137         }
 138
 139         /**
 140          * Returns all artists involved in the track with the given ID.
 141          *
 142          * @param trackId
 143          *            The ID of the track
 144          * @return All artists involved in the track, in preferred order
 145          * @throws DatabaseException
 146          *             if a database error occurs
 147          */
 148         public List<Artist> getArtistsByTrack(String trackId) throws DatabaseException {
 149                 Query query = new Query(Type.SELECT, "ARTISTS");
 150                 query.addField(new Field("ARTISTS.*"));
 151                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACK_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 152                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(trackId))));
 153                 query.addOrderField(new OrderField(new Field("TRACK_ARTISTS.DISPLAY_ORDER")));
 154                 return loadArtistProperties(database.getMultiple(query, artistCreator));
 155         }
 156
 157         /**
 158          * Creates a new artist with the given name.
 159          *
 160          * @param name
 161          *            The name of the artist
 162          * @return The created artist
 163          * @throws DatabaseException
 164          *             if a database error occurs
 165          */
 166         public Artist createArtist(String name) throws DatabaseException {
 167                 Query query = new Query(Type.INSERT, "ARTISTS");
 168                 String id = UUID.randomUUID().toString();
 169                 query.addValueField(new ValueField("ID", new StringParameter(id)));
 170                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
 171                 database.insert(query);
 172                 return loadArtistProperties(getArtistById(id));
 173         }
 174
 175         /**
 176          * Saves the given artist.
 177          *
 178          * @param artist
 179          *            The artist to save
 180          * @throws DatabaseException
 181          *             if a database error occurs
 182          */
 183         public void saveArtist(Artist artist) throws DatabaseException {
 184                 Query query = new Query(Type.UPDATE, "ARTISTS");
 185                 query.addValueField(new ValueField("NAME", new StringParameter(artist.getName())));
 186                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ID", new StringParameter(artist.getId()))));
 187                 database.update(query);
 188                 saveArtistProperties(artist);
 189         }
 190
 191         /**
 192          * Saves the properties of the given artist.
 193          *
 194          * @param artist
 195          *            The artist whose properties to save
 196          * @throws DatabaseException
 197          *             if a database error occurs
 198          */
 199         public void saveArtistProperties(Artist artist) throws DatabaseException {
 200                 saveProperties(artist.getProperties(), "ARTIST_PROPERTIES", "ARTIST", artist.getId());
 201         }
 202
 203         /**
 204          * Saves the given properties to the given table for the given principal.
 205          *
 206          * @param properties
 207          *            The properties to save
 208          * @param table
 209          *            The table in which to save the properties
 210          * @param type
 211          *            The type of the principal (e. g. “ARTIST” or “TRACK”)
 212          * @param id
 213          *            The ID of the principial
 214          * @throws DatabaseException
 215          *             if a database error occurs
 216          */
 217         public void saveProperties(Properties properties, String table, String type, String id) throws DatabaseException {
 218                 if (!properties.isDirty()) {
 219                         return;
 220                 }
 221                 Query query = new Query(Type.DELETE, table);
 222                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(id))));
 223                 database.update(query);
 224                 for (Entry<String, String> property : properties) {
 225                         Query insertQuery = new Query(Type.INSERT, table);
 226                         insertQuery.addValueField(new ValueField(type, new StringParameter(id)));
 227                         insertQuery.addValueField(new ValueField("PROPERTY", new StringParameter(property.getKey())));
 228                         insertQuery.addValueField(new ValueField("VALUE", new StringParameter(property.getValue())));
 229                         database.insert(insertQuery);
 230                 }
 231                 properties.resetDirty();
 232         }
 233
 234         /**
 235          * Loads the properties for an artist.
 236          *
 237          * @param artist
 238          *            The artist to load the properties for
 239          * @return The artist
 240          * @throws DatabaseException
 241          *             if a database error occurs
 242          */
 243         public Artist loadArtistProperties(final Artist artist) throws DatabaseException {
 244                 return loadProperties(artist, "ARTIST_PROPERTIES", "ARTIST");
 245         }
 246
 247         /**
 248          * Loads the properties of all given artists.
 249          *
 250          * @param artists
 251          *            The artists to load the properties for
 252          * @return The list of artists
 253          * @throws DatabaseException
 254          *             if a database error occurs
 255          */
 256         public List<Artist> loadArtistProperties(List<Artist> artists) throws DatabaseException {
 257                 for (Artist artist : artists) {
 258                         loadArtistProperties(artist);
 259                 }
 260                 return artists;
 261         }
 262
 263         /**
 264          * Returns all remix artists involved in the track with the given ID.
 265          *
 266          * @param trackId
 267          *            The ID of the track
 268          * @return All remix artists involved in the track, in preferred order
 269          * @throws DatabaseException
 270          *             if a database error occurs
 271          */
 272         public List<Artist> getRemixArtistsByTrack(String trackId) throws DatabaseException {
 273                 Query query = new Query(Type.SELECT, "ARTISTS");
 274                 query.addField(new Field("ARTISTS.*"));
 275                 query.addJoin(new Join(JoinType.INNER, "TRACK_REMIX_ARTISTS", new Field("TRACK_REMIX_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 276                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_REMIX_ARTISTS.TRACK", new StringParameter(trackId))));
 277                 query.addOrderField(new OrderField(new Field("TRACK_REMIX_ARTISTS.DISPLAY_ORDER")));
 278                 return database.getMultiple(query, artistCreator);
 279         }
 280
 281         /**
 282          * Returns all related tracks for the track with the given ID.
 283          *
 284          * @param trackId
 285          *            The ID of the tracks
 286          * @return A mapping from relationship to all tracks that match the relation
 287          * @throws DatabaseException
 288          *             if a database error occurs
 289          */
 290         public Map<Relationship, Collection<Track>> getRelatedTracksByTrack(String trackId) throws DatabaseException {
 291                 Query query = new Query(Type.SELECT, "TRACKS");
 292                 query.addField(new Field("TRACKS.*"));
 293                 query.addField(new Field("TRACK_RELATIONS.*"));
 294                 query.addJoin(new Join(JoinType.INNER, "TRACK_RELATIONS", new Field("TRACK_RELATIONS.TRACK"), new Field("TRACK_RELATIONS.RELATED_TRACK")));
 295                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_RELATIONS.TRACK", new StringParameter(trackId))));
 296                 final Map<Relationship, Collection<Track>> relatedTracks = new EnumMap<Relationship, Collection<Track>>(Relationship.class);
 297                 database.process(query, new ResultProcessor() {
 298
 299                         @Override
 300                         @SuppressWarnings("synthetic-access")
 301                         public void processResult(ResultSet resultSet) throws SQLException {
 302                                 Track track = trackCreator.createObject(resultSet);
 303                                 Relationship relationship = Relationship.valueOf(resultSet.getString("TRACK_RELATIONS.RELATIONSHIP"));
 304                                 if (!relatedTracks.containsKey(relationship)) {
 305                                         relatedTracks.put(relationship, new HashSet<Track>());
 306                                 }
 307                                 relatedTracks.get(relationship).add(track);
 308                         }
 309                 });
 310                 return relatedTracks;
 311         }
 312
 313         /**
 314          * Returns the track with the given ID.
 315          *
 316          * @param id
 317          *            The ID of the track
 318          * @return The track with the given ID, or {@code null} if there is no such
 319          *         track
 320          * @throws DatabaseException
 321          *             if a database error occurs
 322          */
 323         public Track getTrackById(String id) throws DatabaseException {
 324                 Query query = new Query(Type.SELECT, "TRACKS");
 325                 query.addField(new Field("TRACKS.*"));
 326                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(id))));
 327                 return loadTrackProperties(database.getSingle(query, trackCreator));
 328         }
 329
 330         /**
 331          * Returns all tracks by the artist with the given ID.
 332          *
 333          * @param artistId
 334          *            The ID of the artist
 335          * @return All tracks by the given artist
 336          * @throws DatabaseException
 337          *             if a database error occurs
 338          */
 339         public Collection<Track> getTracksByArtist(String artistId) throws DatabaseException {
 340                 Query query = new Query(Type.SELECT, "TRACKS");
 341                 query.addField(new Field("TRACKS.*"));
 342                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACKS.ID"), new Field("TRACK_ARTISTS.TRACK")));
 343                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(artistId))));
 344                 return loadTrackProperties(database.getMultiple(query, trackCreator));
 345         }
 346
 347         /**
 348          * Loads the properties for the given track.
 349          *
 350          * @param track
 351          *            The track for which to load the properties
 352          * @return The track with the properties loaded
 353          * @throws DatabaseException
 354          *             if a database error occurs
 355          */
 356         public Track loadTrackProperties(Track track) throws DatabaseException {
 357                 return loadProperties(track, "TRACK_PROPERTIES", "TRACK");
 358         }
 359
 360         /**
 361          * Loads the properties for the given tracks.
 362          *
 363          * @param tracks
 364          *            The tracks for which to load the properties
 365          * @return The tracks with the properties loaded
 366          * @throws DatabaseException
 367          *             if a database error occurs
 368          */
 369         public List<Track> loadTrackProperties(List<Track> tracks) throws DatabaseException {
 370                 for (Track track : tracks) {
 371                         loadTrackProperties(track);
 372                 }
 373                 return tracks;
 374         }
 375
 376         /**
 377          * Creates a new track with the given name.
 378          *
 379          * @param name
 380          *            The name of the track
 381          * @return The created track
 382          * @throws DatabaseException
 383          *             if a database error occurs
 384          */
 385         public Track createTrack(String name) throws DatabaseException {
 386                 Query query = new Query(Type.INSERT, "TRACKS");
 387                 String id = UUID.randomUUID().toString();
 388                 query.addValueField(new ValueField("ID", new StringParameter(id)));
 389                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
 390                 database.insert(query);
 391                 return getTrackById(id);
 392         }
 393
 394         /**
 395          * Returns the derivative with the given ID.
 396          *
 397          * @param id
 398          *            The ID of the derivatives to load
 399          * @return The derivative with the given ID
 400          * @throws DatabaseException
 401          *             if a database error occurs
 402          */
 403         public TrackDerivative getTrackDerivativeById(String id) throws DatabaseException {
 404                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 405                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 406                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id))));
 407                 return loadTrackDerivativeProperties(database.getSingle(query, trackDerivativeCreator));
 408         }
 409
 410         /**
 411          * Returns the derivatives for the given track.
 412          *
 413          * @param trackId
 414          *            The track ID to get the derivatives for
 415          * @return The derivatives for the given track
 416          * @throws DatabaseException
 417          *             if a database error occurs
 418          */
 419         public Collection<TrackDerivative> getTrackDerivativesByTrack(String trackId) throws DatabaseException {
 420                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 421                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 422                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(trackId))));
 423                 return loadTrackDerivativeProperties(database.getMultiple(query, trackDerivativeCreator));
 424         }
 425
 426         /**
 427          * Creates a new derivative for the given track.
 428          *
 429          * @param track
 430          *            The track to create the derivative for
 431          * @return The created derivative
 432          * @throws DatabaseException
 433          *             if a database error occurs
 434          */
 435         public TrackDerivative createTrackDerivative(Track track) throws DatabaseException {
 436                 Query query = new Query(Type.INSERT, "TRACK_DERIVATIVES");
 437                 String id = UUID.randomUUID().toString();
 438                 query.addValueField(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id)));
 439                 query.addValueField(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(track.getId())));
 440                 database.insert(query);
 441                 return getTrackDerivativeById(id);
 442         }
 443
 444         /**
 445          * Loads the properties for the given track derivative.
 446          *
 447          * @param trackDerivative
 448          *            The track derivative to load the properties for
 449          * @return The track derivative with its properties loaded
 450          * @throws DatabaseException
 451          *             if a database error occurs
 452          */
 453         public TrackDerivative loadTrackDerivativeProperties(TrackDerivative trackDerivative) throws DatabaseException {
 454                 return loadProperties(trackDerivative, "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE");
 455         }
 456
 457         /**
 458          * Loads the properties for the given track derivatives.
 459          *
 460          * @param trackDerivatives
 461          *            The track derivatives to load the properties for
 462          * @return The track derivatives with their properties loaded
 463          * @throws DatabaseException
 464          *             if a database error occurs
 465          */
 466         public List<TrackDerivative> loadTrackDerivativeProperties(List<TrackDerivative> trackDerivatives) throws DatabaseException {
 467                 for (TrackDerivative trackDerivative : trackDerivatives) {
 468                         loadTrackDerivativeProperties(trackDerivative);
 469                 }
 470                 return trackDerivatives;
 471         }
 472
 473         /**
 474          * Returns all groups the artist with the given ID belongs to.
 475          *
 476          * @param artistId
 477          *            The ID of the artist
 478          * @return All groups the artist belongs to
 479          * @throws DatabaseException
 480          *             if a database error occurs
 481          */
 482         public Collection<Group> getGroupsByArtist(String artistId) throws DatabaseException {
 483                 Query query = new Query(Type.SELECT, "GROUPS");
 484                 query.addField(new Field("GROUPS.*"));
 485                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("GROUPS.ID"), new Field("GROUP_ARTISTS.GROUP_")));
 486                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artistId))));
 487                 return database.getMultiple(query, groupCreator);
 488         }
 489
 490         /**
 491          * Returns all styles for the track with the given ID.
 492          *
 493          * @param trackId
 494          *            The ID of the track
 495          * @return All styles for the given track
 496          * @throws DatabaseException
 497          *             if a database error occurs
 498          */
 499         public Collection<Style> getStylesByTrack(String trackId) throws DatabaseException {
 500                 Query query = new Query(Type.SELECT, "STYLES");
 501                 query.addField(new Field("STYLES.*"));
 502                 query.addJoin(new Join(JoinType.INNER, "TRACK_STYLES", new Field("STYLES.ID"), new Field("TRACK_STYLES.STYLE")));
 503                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_STYLES.TRACK", new StringParameter(trackId))));
 504                 return database.getMultiple(query, styleCreator);
 505         }
 506
 507         /**
 508          * Returns the user with the given name.
 509          *
 510          * @param username
 511          *            The name of the user
 512          * @return The user, or {@code null} if the user does not exist
 513          * @throws DatabaseException
 514          *             if a database error occurs
 515          */
 516         public User getUserByName(String username) throws DatabaseException {
 517                 Query query = new Query(Type.SELECT, "USERS");
 518                 query.addField(new Field("USERS.*"));
 519                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USERS.NAME", new StringParameter(username))));
 520                 return database.getSingle(query, userCreator);
 521         }
 522
 523         /**
 524          * Returns the user connected with the given OpenID.
 525          *
 526          * @param openId
 527          *            The OpenID to find the user for
 528          * @return The user connected with the given OpenID, or {@code null} if
 529          *         there is no such user
 530          * @throws DatabaseException
 531          *             if a database error occurs
 532          */
 533         public User getUserByOpenId(String openId) throws DatabaseException {
 534                 Query query = new Query(Type.SELECT, "USERS");
 535                 query.addField(new Field("USERS.*"));
 536                 query.addJoin(new Join(JoinType.INNER, "USER_OPENIDS", new Field("USER_OPENIDS.USER"), new Field("USERS.ID")));
 537                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.OPENID", new StringParameter(openId))));
 538                 return database.getSingle(query, userCreator);
 539         }
 540
 541         /**
 542          * Returns all OpenIDs connected with the user with the given ID.
 543          *
 544          * @param userId
 545          *            The ID of the user
 546          * @return All OpenIDs connected with the given user
 547          * @throws DatabaseException
 548          *             if a database error occurs
 549          */
 550         public Collection<String> getOpenIdsByUser(String userId) throws DatabaseException {
 551                 Query query = new Query(Type.SELECT, "USER_OPENIDS");
 552                 query.addField(new Field("USER_OPENIDS.*"));
 553                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.USER", new StringParameter(userId))));
 554                 return database.getMultiple(query, new StringCreator("USER_OPENIDS.OPENID"));
 555         }
 556
 557         //
 558         // PRIVATE METHODS
 559         //
 560
 561         /**
 562          * Loads the properties for the given object.
 563          *
 564          * @param <T>
 565          *            The type of the object
 566          * @param object
 567          *            The object
 568          * @param table
 569          *            The table to load the properties from
 570          * @param type
 571          *            The type of the object (“ARTIST,” “TRACK,” etc.)
 572          * @return The object with its properties loaded
 573          * @throws DatabaseException
 574          *             if a database error occurs
 575          */
 576         private <T extends Base> T loadProperties(final T object, final String table, String type) throws DatabaseException {
 577                 Query query = new Query(Type.SELECT, table);
 578                 query.addField(new Field(table + ".PROPERTY"));
 579                 query.addField(new Field(table + ".VALUE"));
 580                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(object.getId()))));
 581                 database.process(query, new ResultProcessor() {
 582
 583                         @Override
 584                         public void processResult(ResultSet resultSet) throws SQLException {
 585                                 if (resultSet.isFirst()) {
 586                                         object.getProperties().removeAll();
 587                                 }
 588                                 object.getProperties().set(resultSet.getString(table + ".PROPERTY"), resultSet.getString(table + ".VALUE"));
 589                         }
 590
 591                 });
 592                 return object;
 593         }
 594
 595         /**
 596          * {@link Artist} implementation that retrieves some attributes (such as
 597          * {@link #getGroups()}, and {@link #getTracks()}) from the
 598          * {@link DataManager} on demand.
 599          *
 600          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 601          */
 602         private class LazyArtist extends DefaultArtist {
 603
 604                 /** Memoizer for the tracks by this artist. */
 605                 private final Memoizer<Void> tracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 606                         @Override
 607                         public Void call() throws DatabaseException {
 608                                 if (!hasValue("tracks")) {
 609                                         getValue("tracks", Collection.class).set(getTracksByArtist(getId()));
 610                                 }
 611                                 return null;
 612                         }
 613                 });
 614
 615                 /** Memoizer for the groups of this artist. */
 616                 private final Memoizer<Void> groupsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 617
 618                         @Override
 619                         public Void call() throws Exception {
 620                                 if (!hasValue("groups")) {
 621                                         getValue("groups", Collection.class).set(getGroupsByArtist(getId()));
 622                                 }
 623                                 return null;
 624                         }
 625
 626                 });
 627
 628                 /**
 629                  * Creates a new lazy artist.
 630                  *
 631                  * @param id
 632                  *            The ID of the artist
 633                  */
 634                 public LazyArtist(String id) {
 635                         super(id);
 636                 }
 637
 638                 //
 639                 // DEFAULTARTIST METHODS
 640                 //
 641
 642                 /**
 643                  * {@inheritDoc}
 644                  */
 645                 @Override
 646                 public Collection<Group> getGroups() {
 647                         groupsMemoizer.get();
 648                         return super.getGroups();
 649                 }
 650
 651                 /**
 652                  * {@inheritDoc}
 653                  */
 654                 @Override
 655                 public Collection<Track> getTracks() {
 656                         tracksMemoizer.get();
 657                         return super.getTracks();
 658                 }
 659
 660         }
 661
 662         /**
 663          * {@link ObjectCreator} implementation that can create {@link Artist}
 664          * objects. This specific class actually creates {@link LazyArtist}
 665          * instances.
 666          *
 667          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 668          */
 669         private class ArtistCreator implements ObjectCreator<Artist> {
 670
 671                 /**
 672                  * {@inheritDoc}
 673                  */
 674                 @Override
 675                 public Artist createObject(ResultSet resultSet) throws SQLException {
 676                         return new LazyArtist(resultSet.getString("ARTISTS.ID")).setName(resultSet.getString("ARTISTS.NAME"));
 677                 }
 678
 679         }
 680
 681         /**
 682          * {@link Group} implementation that retrieves some attributes (such as
 683          * {@link #getArtists()}) from the {@link DataManager} on demand.
 684          *
 685          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 686          */
 687         private class LazyGroup extends DefaultGroup {
 688
 689                 /** Memoizer for the artist. */
 690                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 691
 692                         @Override
 693                         public Void call() throws Exception {
 694                                 if (!hasValue("artists")) {
 695                                         getValue("artists", Collection.class).set(getArtistsByGroup(getId()));
 696                                 }
 697                                 return null;
 698                         }
 699
 700                 });
 701
 702                 /**
 703                  * Creates a new lazy group.
 704                  *
 705                  * @param id
 706                  *            The ID of the group
 707                  */
 708                 public LazyGroup(String id) {
 709                         super(id);
 710                 }
 711
 712                 //
 713                 // DEFAULTGROUP METHODS
 714                 //
 715
 716                 /**
 717                  * {@inheritDoc}
 718                  */
 719                 @Override
 720                 public Collection<Artist> getArtists() {
 721                         artistsMemoizer.get();
 722                         return super.getArtists();
 723                 }
 724
 725         }
 726
 727         /**
 728          * {@link ObjectCreator} implementation that can create {@link Group}
 729          * objects. This specific implementation creates {@link LazyGroup}
 730          * instances.
 731          *
 732          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 733          */
 734         private class GroupCreator implements ObjectCreator<Group> {
 735
 736                 /**
 737                  * {@inheritDoc}
 738                  */
 739                 @Override
 740                 public Group createObject(ResultSet resultSet) throws SQLException {
 741                         return new LazyGroup(resultSet.getString("GROUPS.ID")).setName(resultSet.getString("GROUPS.NAME")).setUrl(resultSet.getString("GROUPS.URL"));
 742                 }
 743
 744         }
 745
 746         /**
 747          * {@link Track} implementation that retrieves some attributes (such as
 748          * {@link #getArtists()}, and {@link #getStyles()}) from the
 749          * {@link DataManager} on demand.
 750          *
 751          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 752          */
 753         private class LazyTrack extends DefaultTrack {
 754
 755                 /** Memoizer for the artists. */
 756                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 757
 758                         @Override
 759                         public Void call() throws Exception {
 760                                 if (!hasValue("artists")) {
 761                                         getValue("artists", List.class).set(getArtistsByTrack(getId()));
 762                                 }
 763                                 return null;
 764                         }
 765
 766                 });
 767
 768                 /** Memoizer for the styles. */
 769                 private final Memoizer<Void> stylesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 770
 771                         @Override
 772                         public Void call() throws Exception {
 773                                 if (!hasValue("styles")) {
 774                                         getValue("styles", Collection.class).set(getStylesByTrack(getId()));
 775                                 }
 776                                 return null;
 777                         }
 778
 779                 });
 780
 781                 /** Memoizer for the remix artists. */
 782                 private final Memoizer<Void> remixArtistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 783
 784                         @Override
 785                         public Void call() throws Exception {
 786                                 if (!hasValue("remixArtists")) {
 787                                         getValue("remixArtists", List.class).set(getRemixArtistsByTrack(getId()));
 788                                 }
 789                                 return null;
 790                         }
 791
 792                 });
 793
 794                 /** Memoizer for the track derivatives. */
 795                 private final Memoizer<Void> derivativesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 796
 797                         @Override
 798                         public Void call() throws Exception {
 799                                 if (!hasValue("derivatives")) {
 800                                         getValue("derivatives", Collection.class).set(getTrackDerivativesByTrack(getId()));
 801                                 }
 802                                 return null;
 803                         }
 804
 805                 });
 806
 807                 /** Memoizer for the related tracks. */
 808                 private final Memoizer<Void> relatedTracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 809
 810                         @Override
 811                         public Void call() throws Exception {
 812                                 if (!hasValue("relatedTracks")) {
 813                                         getValue("relatedTracks", Map.class).set(getRelatedTracksByTrack(getId()));
 814                                 }
 815                                 return null;
 816                         }
 817                 });
 818
 819                 /**
 820                  * Creates a new track.
 821                  *
 822                  * @param id
 823                  *            The ID of the track
 824                  */
 825                 public LazyTrack(String id) {
 826                         super(id);
 827                 }
 828
 829                 //
 830                 // DEFAULTTRACK METHODS
 831                 //
 832
 833                 /**
 834                  * {@inheritDoc}
 835                  */
 836                 @Override
 837                 public List<Artist> getArtists() {
 838                         artistsMemoizer.get();
 839                         return super.getArtists();
 840                 }
 841
 842                 /**
 843                  * {@inheritDoc}
 844                  */
 845                 @Override
 846                 public Collection<Style> getStyles() {
 847                         stylesMemoizer.get();
 848                         return super.getStyles();
 849                 }
 850
 851                 /**
 852                  * {@inheritDoc}
 853                  */
 854                 @Override
 855                 public List<Artist> getRemixArtists() {
 856                         remixArtistsMemoizer.get();
 857                         return super.getRemixArtists();
 858                 }
 859
 860                 /**
 861                  * {@inheritDoc}
 862                  */
 863                 @Override
 864                 public Collection<TrackDerivative> getDerivatives() {
 865                         derivativesMemoizer.get();
 866                         return super.getDerivatives();
 867                 }
 868
 869                 /**
 870                  * {@inheritDoc}
 871                  */
 872                 @Override
 873                 public Map<Relationship, Collection<Track>> getRelatedTracks() {
 874                         relatedTracksMemoizer.get();
 875                         return super.getRelatedTracks();
 876                 }
 877
 878         }
 879
 880         /**
 881          * {@link ObjectCreator} implementation that can create {@link Track}
 882          * objects. This specific implementation creates {@link LazyTrack}
 883          * instances.
 884          *
 885          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 886          */
 887         private class TrackCreator implements ObjectCreator<Track> {
 888
 889                 /**
 890                  * {@inheritDoc}
 891                  */
 892                 @Override
 893                 public Track createObject(ResultSet resultSet) throws SQLException {
 894                         return new LazyTrack(resultSet.getString("TRACKS.ID")).setName(resultSet.getString("TRACKS.NAME")).setRemix(resultSet.getString("TRACKS.REMIX"));
 895                 }
 896
 897         }
 898
 899         /**
 900          * {@link ObjectCreator} implementation that can create
 901          * {@link TrackDerivative} objects.
 902          *
 903          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 904          */
 905         private class TrackDerivativeCreator implements ObjectCreator<TrackDerivative> {
 906
 907                 /**
 908                  * {@inheritDoc}
 909                  */
 910                 @Override
 911                 public TrackDerivative createObject(ResultSet resultSet) throws SQLException {
 912                         return new DefaultTrackDerivative(resultSet.getString("TRACK_DERIVATIVES.ID"));
 913                 }
 914
 915         }
 916
 917         /**
 918          * {@link ObjectCreator} implementation that can create {@link Style}
 919          * objects.
 920          *
 921          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 922          */
 923         private class StyleCreator implements ObjectCreator<Style> {
 924
 925                 /**
 926                  * {@inheritDoc}
 927                  */
 928                 @Override
 929                 public Style createObject(ResultSet resultSet) throws SQLException {
 930                         return new DefaultStyle(resultSet.getString("STYLES.ID")).setName(resultSet.getString("STYLES.NAME"));
 931                 }
 932
 933         }
 934
 935         /**
 936          * {@link User} implementation that retrieves some attributes (such as
 937          * {@link #getOpenIds()}) from the {@link DataManager} on demand.
 938          *
 939          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 940          */
 941         private class LazyUser extends DefaultUser {
 942
 943                 /** Memoizer for a user’s OpenIDs. */
 944                 private final Memoizer<Void> openIdMemoizer = new Memoizer<Void>(new Callable<Void>() {
 945
 946                         @Override
 947                         public Void call() throws Exception {
 948                                 if (!hasValue("openIds")) {
 949                                         getValue("openIds", Collection.class).set(getOpenIdsByUser(getId()));
 950                                 }
 951                                 return null;
 952                         }
 953                 });
 954
 955                 /**
 956                  * Creates a new user.
 957                  *
 958                  * @param id
 959                  *            The ID of the user
 960                  */
 961                 public LazyUser(String id) {
 962                         super(id);
 963                 }
 964
 965                 /**
 966                  * {@inheritDoc}
 967                  */
 968                 @Override
 969                 public Collection<String> getOpenIds() {
 970                         openIdMemoizer.get();
 971                         return super.getOpenIds();
 972                 }
 973
 974         }
 975
 976         /**
 977          * {@link ObjectCreator} implementation that can create {@link User}
 978          * objects. This specific implementation creates {@link LazyUser} instances.
 979          *
 980          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 981          */
 982         private class UserCreator implements ObjectCreator<User> {
 983
 984                 /**
 985                  * {@inheritDoc}
 986                  */
 987                 @Override
 988                 public User createObject(ResultSet resultSet) throws SQLException {
 989                         return new LazyUser(resultSet.getString("USERS.ID")).setName(resultSet.getString("USERS.NAME")).setPasswordHash(resultSet.getString("USERS.PASSWORD")).setLevel(resultSet.getInt("USERS.LEVEL"));
 990                 }
 991
 992         }
 993
 994 }