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 {@link User} object creator. */
  77         @SuppressWarnings("synthetic-access")
  78         private final ObjectCreator<User> userCreator = new UserCreator();
  79
  80         /** The database. */
  81         private final Database database;
  82
  83         /**
  84          * Creates a new data manager.
  85          *
  86          * @param database
  87          *            The database to operate on
  88          */
  89         public DataManager(Database database) {
  90                 this.database = database;
  91         }
  92
  93         /**
  94          * Returns all artists.
  95          *
  96          * @return All artists
  97          * @throws DatabaseException
  98          *             if a database error occurs
  99          */
 100         public Collection<Artist> getAllArtists() throws DatabaseException {
 101                 Query query = new Query(Type.SELECT, "ARTISTS");
 102                 query.addField(new Field("ARTISTS.*"));
 103                 return loadArtistProperties(database.getMultiple(query, artistCreator));
 104         }
 105
 106         /**
 107          * Returns the artist with the given ID.
 108          *
 109          * @param id
 110          *            The ID of the artist
 111          * @return The artist with the given ID, or {@code null} if there is no
 112          *         artist with the given ID
 113          * @throws DatabaseException
 114          *             if a database error occurs
 115          */
 116         public Artist getArtistById(String id) throws DatabaseException {
 117                 Query query = new Query(Type.SELECT, "ARTISTS");
 118                 query.addField(new Field("ARTISTS.*"));
 119                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ARTISTS.ID", new StringParameter(id))));
 120                 return loadArtistProperties(database.getSingle(query, artistCreator));
 121         }
 122
 123         /**
 124          * Returns all artists that belong to the group with the given ID.
 125          *
 126          * @param groupId
 127          *            The ID of the group
 128          * @return All artists belonging to the given group
 129          * @throws DatabaseException
 130          *             if a database error occurs
 131          */
 132         public Collection<Artist> getArtistsByGroup(String groupId) throws DatabaseException {
 133                 Query query = new Query(Type.SELECT, "ARTISTS");
 134                 query.addField(new Field("ARTISTS.*"));
 135                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("ARTISTS.ID"), new Field("GROUP_ARTISTS.ARTIST")));
 136                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.GROUP_", new StringParameter(groupId))));
 137                 return loadArtistProperties(database.getMultiple(query, artistCreator));
 138         }
 139
 140         /**
 141          * Returns all artists involved in the track with the given ID.
 142          *
 143          * @param trackId
 144          *            The ID of the track
 145          * @return All artists involved in the track, in preferred order
 146          * @throws DatabaseException
 147          *             if a database error occurs
 148          */
 149         public List<Artist> getArtistsByTrack(String trackId) throws DatabaseException {
 150                 Query query = new Query(Type.SELECT, "ARTISTS");
 151                 query.addField(new Field("ARTISTS.*"));
 152                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACK_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 153                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(trackId))));
 154                 query.addOrderField(new OrderField(new Field("TRACK_ARTISTS.DISPLAY_ORDER")));
 155                 return loadArtistProperties(database.getMultiple(query, artistCreator));
 156         }
 157
 158         /**
 159          * Creates a new artist with the given name.
 160          *
 161          * @param name
 162          *            The name of the artist
 163          * @return The created artist
 164          * @throws DatabaseException
 165          *             if a database error occurs
 166          */
 167         public Artist createArtist(String name) throws DatabaseException {
 168                 Query query = new Query(Type.INSERT, "ARTISTS");
 169                 String id = UUID.randomUUID().toString();
 170                 query.addValueField(new ValueField("ID", new StringParameter(id)));
 171                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
 172                 database.insert(query);
 173                 return loadArtistProperties(getArtistById(id));
 174         }
 175
 176         /**
 177          * Saves the given artist.
 178          *
 179          * @param artist
 180          *            The artist to save
 181          * @throws DatabaseException
 182          *             if a database error occurs
 183          */
 184         public void saveArtist(Artist artist) throws DatabaseException {
 185                 Query query = new Query(Type.UPDATE, "ARTISTS");
 186                 query.addValueField(new ValueField("NAME", new StringParameter(artist.getName())));
 187                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ID", new StringParameter(artist.getId()))));
 188                 database.update(query);
 189                 saveArtistProperties(artist);
 190         }
 191
 192         /**
 193          * Saves the properties of the given artist.
 194          *
 195          * @param artist
 196          *            The artist whose properties to save
 197          * @throws DatabaseException
 198          *             if a database error occurs
 199          */
 200         public void saveArtistProperties(Artist artist) throws DatabaseException {
 201                 saveProperties(artist.getProperties(), "ARTIST_PROPERTIES", "ARTIST", artist.getId());
 202         }
 203
 204         /**
 205          * Saves the given properties to the given table for the given principal.
 206          *
 207          * @param properties
 208          *            The properties to save
 209          * @param table
 210          *            The table in which to save the properties
 211          * @param type
 212          *            The type of the principal (e. g. “ARTIST” or “TRACK”)
 213          * @param id
 214          *            The ID of the principial
 215          * @throws DatabaseException
 216          *             if a database error occurs
 217          */
 218         public void saveProperties(Properties properties, String table, String type, String id) throws DatabaseException {
 219                 if (!properties.isDirty()) {
 220                         return;
 221                 }
 222                 Query query = new Query(Type.DELETE, table);
 223                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(id))));
 224                 database.update(query);
 225                 for (Entry<String, String> property : properties) {
 226                         Query insertQuery = new Query(Type.INSERT, table);
 227                         insertQuery.addValueField(new ValueField(type, new StringParameter(id)));
 228                         insertQuery.addValueField(new ValueField("PROPERTY", new StringParameter(property.getKey())));
 229                         insertQuery.addValueField(new ValueField("VALUE", new StringParameter(property.getValue())));
 230                         database.insert(insertQuery);
 231                 }
 232                 properties.resetDirty();
 233         }
 234
 235         /**
 236          * Loads the properties for an artist.
 237          *
 238          * @param artist
 239          *            The artist to load the properties for
 240          * @return The artist
 241          * @throws DatabaseException
 242          *             if a database error occurs
 243          */
 244         public Artist loadArtistProperties(final Artist artist) throws DatabaseException {
 245                 return loadProperties(artist, "ARTIST_PROPERTIES", "ARTIST");
 246         }
 247
 248         /**
 249          * Loads the properties of all given artists.
 250          *
 251          * @param artists
 252          *            The artists to load the properties for
 253          * @return The list of artists
 254          * @throws DatabaseException
 255          *             if a database error occurs
 256          */
 257         public List<Artist> loadArtistProperties(List<Artist> artists) throws DatabaseException {
 258                 for (Artist artist : artists) {
 259                         loadArtistProperties(artist);
 260                 }
 261                 return artists;
 262         }
 263
 264         /**
 265          * Returns all remix artists involved in the track with the given ID.
 266          *
 267          * @param trackId
 268          *            The ID of the track
 269          * @return All remix artists involved in the track, in preferred order
 270          * @throws DatabaseException
 271          *             if a database error occurs
 272          */
 273         public List<Artist> getRemixArtistsByTrack(String trackId) throws DatabaseException {
 274                 Query query = new Query(Type.SELECT, "ARTISTS");
 275                 query.addField(new Field("ARTISTS.*"));
 276                 query.addJoin(new Join(JoinType.INNER, "TRACK_REMIX_ARTISTS", new Field("TRACK_REMIX_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 277                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_REMIX_ARTISTS.TRACK", new StringParameter(trackId))));
 278                 query.addOrderField(new OrderField(new Field("TRACK_REMIX_ARTISTS.DISPLAY_ORDER")));
 279                 return database.getMultiple(query, artistCreator);
 280         }
 281
 282         /**
 283          * Returns all related tracks for the track with the given ID.
 284          *
 285          * @param trackId
 286          *            The ID of the tracks
 287          * @return A mapping from relationship to all tracks that match the relation
 288          * @throws DatabaseException
 289          *             if a database error occurs
 290          */
 291         public Map<Relationship, Collection<Track>> getRelatedTracksByTrack(String trackId) throws DatabaseException {
 292                 Query query = new Query(Type.SELECT, "TRACKS");
 293                 query.addField(new Field("TRACKS.*"));
 294                 query.addField(new Field("TRACK_RELATIONS.*"));
 295                 query.addJoin(new Join(JoinType.INNER, "TRACK_RELATIONS", new Field("TRACK_RELATIONS.TRACK"), new Field("TRACK_RELATIONS.RELATED_TRACK")));
 296                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_RELATIONS.TRACK", new StringParameter(trackId))));
 297                 final Map<Relationship, Collection<Track>> relatedTracks = new EnumMap<Relationship, Collection<Track>>(Relationship.class);
 298                 database.process(query, new ResultProcessor() {
 299
 300                         @Override
 301                         @SuppressWarnings("synthetic-access")
 302                         public void processResult(ResultSet resultSet) throws SQLException {
 303                                 Track track = trackCreator.createObject(resultSet);
 304                                 Relationship relationship = Relationship.valueOf(resultSet.getString("TRACK_RELATIONS.RELATIONSHIP"));
 305                                 if (!relatedTracks.containsKey(relationship)) {
 306                                         relatedTracks.put(relationship, new HashSet<Track>());
 307                                 }
 308                                 relatedTracks.get(relationship).add(track);
 309                         }
 310                 });
 311                 return relatedTracks;
 312         }
 313
 314         /**
 315          * Returns the track with the given ID.
 316          *
 317          * @param id
 318          *            The ID of the track
 319          * @return The track with the given ID, or {@code null} if there is no such
 320          *         track
 321          * @throws DatabaseException
 322          *             if a database error occurs
 323          */
 324         public Track getTrackById(String id) throws DatabaseException {
 325                 Query query = new Query(Type.SELECT, "TRACKS");
 326                 query.addField(new Field("TRACKS.*"));
 327                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(id))));
 328                 return loadTrackProperties(database.getSingle(query, trackCreator));
 329         }
 330
 331         /**
 332          * Returns all tracks by the artist with the given ID.
 333          *
 334          * @param artistId
 335          *            The ID of the artist
 336          * @return All tracks by the given artist
 337          * @throws DatabaseException
 338          *             if a database error occurs
 339          */
 340         public Collection<Track> getTracksByArtist(String artistId) throws DatabaseException {
 341                 Query query = new Query(Type.SELECT, "TRACKS");
 342                 query.addField(new Field("TRACKS.*"));
 343                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACKS.ID"), new Field("TRACK_ARTISTS.TRACK")));
 344                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(artistId))));
 345                 return loadTrackProperties(database.getMultiple(query, trackCreator));
 346         }
 347
 348         /**
 349          * Loads the properties for the given track.
 350          *
 351          * @param track
 352          *            The track for which to load the properties
 353          * @return The track with the properties loaded
 354          * @throws DatabaseException
 355          *             if a database error occurs
 356          */
 357         public Track loadTrackProperties(Track track) throws DatabaseException {
 358                 return loadProperties(track, "TRACK_PROPERTIES", "TRACK");
 359         }
 360
 361         /**
 362          * Loads the properties for the given tracks.
 363          *
 364          * @param tracks
 365          *            The tracks for which to load the properties
 366          * @return The tracks with the properties loaded
 367          * @throws DatabaseException
 368          *             if a database error occurs
 369          */
 370         public List<Track> loadTrackProperties(List<Track> tracks) throws DatabaseException {
 371                 for (Track track : tracks) {
 372                         loadTrackProperties(track);
 373                 }
 374                 return tracks;
 375         }
 376
 377         /**
 378          * Creates a new track with the given name.
 379          *
 380          * @param name
 381          *            The name of the track
 382          * @return The created track
 383          * @throws DatabaseException
 384          *             if a database error occurs
 385          */
 386         public Track createTrack(String name) throws DatabaseException {
 387                 Query query = new Query(Type.INSERT, "TRACKS");
 388                 String id = UUID.randomUUID().toString();
 389                 query.addValueField(new ValueField("ID", new StringParameter(id)));
 390                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
 391                 database.insert(query);
 392                 return getTrackById(id);
 393         }
 394
 395         /**
 396          * Saves the given track. This also saves all relationships of the track.
 397          *
 398          * @param track
 399          *            The track to save
 400          * @throws DatabaseException
 401          *             if a database error occurs
 402          */
 403         public void saveTrack(Track track) throws DatabaseException {
 404                 Query query = new Query(Type.UPDATE, "TRACKS");
 405                 query.addValueField(new ValueField("TRACKS.NAME", new StringParameter(track.getName())));
 406                 query.addValueField(new ValueField("TRACKS.REMIX", new StringParameter(track.getRemix())));
 407                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(track.getId()))));
 408                 database.update(query);
 409                 /* store artist information. */
 410                 track.getArtists(); /* prefetch artists. */
 411                 query = new Query(Type.DELETE, "TRACK_ARTISTS");
 412                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(track.getId()))));
 413                 database.update(query);
 414                 for (int index = 0; index < track.getArtists().size(); ++index) {
 415                         query = new Query(Type.INSERT, "TRACK_ARTISTS");
 416                         query.addValueField(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(track.getId())));
 417                         query.addValueField(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(track.getArtists().get(index).getId())));
 418                         query.addValueField(new ValueField("TRACK_ARTISTS.DISPLAY_ORDER", new IntegerParameter(index + 1)));
 419                         database.insert(query);
 420                 }
 421                 /* store properties. */
 422                 saveProperties(track.getProperties(), "TRACK_PROPERTIES", "TRACK", track.getId());
 423         }
 424
 425         /**
 426          * Returns the derivative with the given ID.
 427          *
 428          * @param id
 429          *            The ID of the derivatives to load
 430          * @return The derivative with the given ID
 431          * @throws DatabaseException
 432          *             if a database error occurs
 433          */
 434         public TrackDerivative getTrackDerivativeById(String id) throws DatabaseException {
 435                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 436                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 437                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id))));
 438                 return loadTrackDerivativeProperties(database.getSingle(query, trackDerivativeCreator));
 439         }
 440
 441         /**
 442          * Returns the derivatives for the given track.
 443          *
 444          * @param trackId
 445          *            The track ID to get the derivatives for
 446          * @return The derivatives for the given track
 447          * @throws DatabaseException
 448          *             if a database error occurs
 449          */
 450         public Collection<TrackDerivative> getTrackDerivativesByTrack(String trackId) throws DatabaseException {
 451                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 452                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 453                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(trackId))));
 454                 return loadTrackDerivativeProperties(database.getMultiple(query, trackDerivativeCreator));
 455         }
 456
 457         /**
 458          * Creates a new derivative for the given track.
 459          *
 460          * @param track
 461          *            The track to create the derivative for
 462          * @return The created derivative
 463          * @throws DatabaseException
 464          *             if a database error occurs
 465          */
 466         public TrackDerivative createTrackDerivative(Track track) throws DatabaseException {
 467                 Query query = new Query(Type.INSERT, "TRACK_DERIVATIVES");
 468                 String id = UUID.randomUUID().toString();
 469                 query.addValueField(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id)));
 470                 query.addValueField(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(track.getId())));
 471                 database.insert(query);
 472                 return getTrackDerivativeById(id);
 473         }
 474
 475         /**
 476          * Loads the properties for the given track derivative.
 477          *
 478          * @param trackDerivative
 479          *            The track derivative to load the properties for
 480          * @return The track derivative with its properties loaded
 481          * @throws DatabaseException
 482          *             if a database error occurs
 483          */
 484         public TrackDerivative loadTrackDerivativeProperties(TrackDerivative trackDerivative) throws DatabaseException {
 485                 return loadProperties(trackDerivative, "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE");
 486         }
 487
 488         /**
 489          * Loads the properties for the given track derivatives.
 490          *
 491          * @param trackDerivatives
 492          *            The track derivatives to load the properties for
 493          * @return The track derivatives with their properties loaded
 494          * @throws DatabaseException
 495          *             if a database error occurs
 496          */
 497         public List<TrackDerivative> loadTrackDerivativeProperties(List<TrackDerivative> trackDerivatives) throws DatabaseException {
 498                 for (TrackDerivative trackDerivative : trackDerivatives) {
 499                         loadTrackDerivativeProperties(trackDerivative);
 500                 }
 501                 return trackDerivatives;
 502         }
 503
 504         /**
 505          * Saves the given track derivative. As a track derivative does not have any
 506          * attributes of its own only its properties are saved.
 507          *
 508          * @param trackDerivative
 509          *            The track derivative to save
 510          * @throws DatabaseException
 511          *             if a database error occurs
 512          */
 513         public void saveTrackDerivate(TrackDerivative trackDerivative) throws DatabaseException {
 514                 saveProperties(trackDerivative.getProperties(), "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE", trackDerivative.getId());
 515         }
 516
 517         /**
 518          * Removes the given track derivative and all its properties from the
 519          * database.
 520          *
 521          * @param trackDerivative
 522          *            The track derivative to remove
 523          * @throws DatabaseException
 524          *             if a database error occurs
 525          */
 526         public void removeTrackDerivative(TrackDerivative trackDerivative) throws DatabaseException {
 527                 Query query = new Query(Type.DELETE, "TRACK_DERIVATIVES");
 528                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(trackDerivative.getId()))));
 529                 database.update(query);
 530                 /* remove the properties. */
 531                 saveProperties(new Properties().set("dirty", "true").removeAll(), "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE", trackDerivative.getId());
 532         }
 533
 534         /**
 535          * Returns all groups the artist with the given ID belongs to.
 536          *
 537          * @param artistId
 538          *            The ID of the artist
 539          * @return All groups the artist belongs to
 540          * @throws DatabaseException
 541          *             if a database error occurs
 542          */
 543         public Collection<Group> getGroupsByArtist(String artistId) throws DatabaseException {
 544                 Query query = new Query(Type.SELECT, "GROUPS");
 545                 query.addField(new Field("GROUPS.*"));
 546                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("GROUPS.ID"), new Field("GROUP_ARTISTS.GROUP_")));
 547                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artistId))));
 548                 return database.getMultiple(query, groupCreator);
 549         }
 550
 551         /**
 552          * Returns all styles for the track with the given ID.
 553          *
 554          * @param trackId
 555          *            The ID of the track
 556          * @return All styles for the given track
 557          * @throws DatabaseException
 558          *             if a database error occurs
 559          */
 560         public Collection<Style> getStylesByTrack(String trackId) throws DatabaseException {
 561                 Query query = new Query(Type.SELECT, "STYLES");
 562                 query.addField(new Field("STYLES.*"));
 563                 query.addJoin(new Join(JoinType.INNER, "TRACK_STYLES", new Field("STYLES.ID"), new Field("TRACK_STYLES.STYLE")));
 564                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_STYLES.TRACK", new StringParameter(trackId))));
 565                 return database.getMultiple(query, styleCreator);
 566         }
 567
 568         /**
 569          * Returns the user with the given name.
 570          *
 571          * @param username
 572          *            The name of the user
 573          * @return The user, or {@code null} if the user does not exist
 574          * @throws DatabaseException
 575          *             if a database error occurs
 576          */
 577         public User getUserByName(String username) throws DatabaseException {
 578                 Query query = new Query(Type.SELECT, "USERS");
 579                 query.addField(new Field("USERS.*"));
 580                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USERS.NAME", new StringParameter(username))));
 581                 return database.getSingle(query, userCreator);
 582         }
 583
 584         /**
 585          * Returns the user connected with the given OpenID.
 586          *
 587          * @param openId
 588          *            The OpenID to find the user for
 589          * @return The user connected with the given OpenID, or {@code null} if
 590          *         there is no such user
 591          * @throws DatabaseException
 592          *             if a database error occurs
 593          */
 594         public User getUserByOpenId(String openId) throws DatabaseException {
 595                 Query query = new Query(Type.SELECT, "USERS");
 596                 query.addField(new Field("USERS.*"));
 597                 query.addJoin(new Join(JoinType.INNER, "USER_OPENIDS", new Field("USER_OPENIDS.USER"), new Field("USERS.ID")));
 598                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.OPENID", new StringParameter(openId))));
 599                 return database.getSingle(query, userCreator);
 600         }
 601
 602         /**
 603          * Returns all OpenIDs connected with the user with the given ID.
 604          *
 605          * @param userId
 606          *            The ID of the user
 607          * @return All OpenIDs connected with the given user
 608          * @throws DatabaseException
 609          *             if a database error occurs
 610          */
 611         public Collection<String> getOpenIdsByUser(String userId) throws DatabaseException {
 612                 Query query = new Query(Type.SELECT, "USER_OPENIDS");
 613                 query.addField(new Field("USER_OPENIDS.*"));
 614                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.USER", new StringParameter(userId))));
 615                 return database.getMultiple(query, new StringCreator("USER_OPENIDS.OPENID"));
 616         }
 617
 618         //
 619         // PRIVATE METHODS
 620         //
 621
 622         /**
 623          * Loads the properties for the given object.
 624          *
 625          * @param <T>
 626          *            The type of the object
 627          * @param object
 628          *            The object
 629          * @param table
 630          *            The table to load the properties from
 631          * @param type
 632          *            The type of the object (“ARTIST,” “TRACK,” etc.)
 633          * @return The object with its properties loaded
 634          * @throws DatabaseException
 635          *             if a database error occurs
 636          */
 637         private <T extends Base> T loadProperties(final T object, final String table, String type) throws DatabaseException {
 638                 Query query = new Query(Type.SELECT, table);
 639                 query.addField(new Field(table + ".PROPERTY"));
 640                 query.addField(new Field(table + ".VALUE"));
 641                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(object.getId()))));
 642                 database.process(query, new ResultProcessor() {
 643
 644                         @Override
 645                         public void processResult(ResultSet resultSet) throws SQLException {
 646                                 if (resultSet.isFirst()) {
 647                                         object.getProperties().removeAll();
 648                                 }
 649                                 object.getProperties().set(resultSet.getString(table + ".PROPERTY"), resultSet.getString(table + ".VALUE"));
 650                         }
 651
 652                 });
 653                 return object;
 654         }
 655
 656         /**
 657          * {@link Artist} implementation that retrieves some attributes (such as
 658          * {@link #getGroups()}, and {@link #getTracks()}) from the
 659          * {@link DataManager} on demand.
 660          *
 661          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 662          */
 663         private class LazyArtist extends DefaultArtist {
 664
 665                 /** Memoizer for the tracks by this artist. */
 666                 private final Memoizer<Void> tracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 667
 668                         @Override
 669                         public Void call() throws DatabaseException {
 670                                 if (!hasValue("tracks")) {
 671                                         getValue("tracks", Collection.class).set(getTracksByArtist(getId()));
 672                                 }
 673                                 return null;
 674                         }
 675                 });
 676
 677                 /** Memoizer for the groups of this artist. */
 678                 private final Memoizer<Void> groupsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 679
 680                         @Override
 681                         public Void call() throws Exception {
 682                                 if (!hasValue("groups")) {
 683                                         getValue("groups", Collection.class).set(getGroupsByArtist(getId()));
 684                                 }
 685                                 return null;
 686                         }
 687
 688                 });
 689
 690                 /**
 691                  * Creates a new lazy artist.
 692                  *
 693                  * @param id
 694                  *            The ID of the artist
 695                  */
 696                 public LazyArtist(String id) {
 697                         super(id);
 698                 }
 699
 700                 //
 701                 // DEFAULTARTIST METHODS
 702                 //
 703
 704                 /**
 705                  * {@inheritDoc}
 706                  */
 707                 @Override
 708                 public Collection<Group> getGroups() {
 709                         groupsMemoizer.get();
 710                         return super.getGroups();
 711                 }
 712
 713                 /**
 714                  * {@inheritDoc}
 715                  */
 716                 @Override
 717                 public Collection<Track> getTracks() {
 718                         tracksMemoizer.get();
 719                         return super.getTracks();
 720                 }
 721
 722         }
 723
 724         /**
 725          * {@link ObjectCreator} implementation that can create {@link Artist}
 726          * objects. This specific class actually creates {@link LazyArtist}
 727          * instances.
 728          *
 729          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 730          */
 731         private class ArtistCreator implements ObjectCreator<Artist> {
 732
 733                 /**
 734                  * {@inheritDoc}
 735                  */
 736                 @Override
 737                 public Artist createObject(ResultSet resultSet) throws SQLException {
 738                         return new LazyArtist(resultSet.getString("ARTISTS.ID")).setName(resultSet.getString("ARTISTS.NAME"));
 739                 }
 740
 741         }
 742
 743         /**
 744          * {@link Group} implementation that retrieves some attributes (such as
 745          * {@link #getArtists()}) from the {@link DataManager} on demand.
 746          *
 747          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 748          */
 749         private class LazyGroup extends DefaultGroup {
 750
 751                 /** Memoizer for the artist. */
 752                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 753
 754                         @Override
 755                         public Void call() throws Exception {
 756                                 if (!hasValue("artists")) {
 757                                         getValue("artists", Collection.class).set(getArtistsByGroup(getId()));
 758                                 }
 759                                 return null;
 760                         }
 761
 762                 });
 763
 764                 /**
 765                  * Creates a new lazy group.
 766                  *
 767                  * @param id
 768                  *            The ID of the group
 769                  */
 770                 public LazyGroup(String id) {
 771                         super(id);
 772                 }
 773
 774                 //
 775                 // DEFAULTGROUP METHODS
 776                 //
 777
 778                 /**
 779                  * {@inheritDoc}
 780                  */
 781                 @Override
 782                 public Collection<Artist> getArtists() {
 783                         artistsMemoizer.get();
 784                         return super.getArtists();
 785                 }
 786
 787         }
 788
 789         /**
 790          * {@link ObjectCreator} implementation that can create {@link Group}
 791          * objects. This specific implementation creates {@link LazyGroup}
 792          * instances.
 793          *
 794          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 795          */
 796         private class GroupCreator implements ObjectCreator<Group> {
 797
 798                 /**
 799                  * {@inheritDoc}
 800                  */
 801                 @Override
 802                 public Group createObject(ResultSet resultSet) throws SQLException {
 803                         return new LazyGroup(resultSet.getString("GROUPS.ID")).setName(resultSet.getString("GROUPS.NAME")).setUrl(resultSet.getString("GROUPS.URL"));
 804                 }
 805
 806         }
 807
 808         /**
 809          * {@link Track} implementation that retrieves some attributes (such as
 810          * {@link #getArtists()}, and {@link #getStyles()}) from the
 811          * {@link DataManager} on demand.
 812          *
 813          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 814          */
 815         private class LazyTrack extends DefaultTrack {
 816
 817                 /** Memoizer for the artists. */
 818                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 819
 820                         @Override
 821                         public Void call() throws Exception {
 822                                 if (!hasValue("artists")) {
 823                                         getValue("artists", List.class).set(getArtistsByTrack(getId()));
 824                                 }
 825                                 return null;
 826                         }
 827
 828                 });
 829
 830                 /** Memoizer for the styles. */
 831                 private final Memoizer<Void> stylesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 832
 833                         @Override
 834                         public Void call() throws Exception {
 835                                 if (!hasValue("styles")) {
 836                                         getValue("styles", Collection.class).set(getStylesByTrack(getId()));
 837                                 }
 838                                 return null;
 839                         }
 840
 841                 });
 842
 843                 /** Memoizer for the remix artists. */
 844                 private final Memoizer<Void> remixArtistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 845
 846                         @Override
 847                         public Void call() throws Exception {
 848                                 if (!hasValue("remixArtists")) {
 849                                         getValue("remixArtists", List.class).set(getRemixArtistsByTrack(getId()));
 850                                 }
 851                                 return null;
 852                         }
 853
 854                 });
 855
 856                 /** Memoizer for the track derivatives. */
 857                 private final Memoizer<Void> derivativesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 858
 859                         @Override
 860                         public Void call() throws Exception {
 861                                 if (!hasValue("derivatives")) {
 862                                         getValue("derivatives", Collection.class).set(getTrackDerivativesByTrack(getId()));
 863                                 }
 864                                 return null;
 865                         }
 866
 867                 });
 868
 869                 /** Memoizer for the related tracks. */
 870                 private final Memoizer<Void> relatedTracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 871
 872                         @Override
 873                         public Void call() throws Exception {
 874                                 if (!hasValue("relatedTracks")) {
 875                                         getValue("relatedTracks", Map.class).set(getRelatedTracksByTrack(getId()));
 876                                 }
 877                                 return null;
 878                         }
 879
 880                 });
 881
 882                 /**
 883                  * Creates a new track.
 884                  *
 885                  * @param id
 886                  *            The ID of the track
 887                  */
 888                 public LazyTrack(String id) {
 889                         super(id);
 890                 }
 891
 892                 //
 893                 // DEFAULTTRACK METHODS
 894                 //
 895
 896                 /**
 897                  * {@inheritDoc}
 898                  */
 899                 @Override
 900                 public List<Artist> getArtists() {
 901                         artistsMemoizer.get();
 902                         return super.getArtists();
 903                 }
 904
 905                 /**
 906                  * {@inheritDoc}
 907                  */
 908                 @Override
 909                 public Collection<Style> getStyles() {
 910                         stylesMemoizer.get();
 911                         return super.getStyles();
 912                 }
 913
 914                 /**
 915                  * {@inheritDoc}
 916                  */
 917                 @Override
 918                 public List<Artist> getRemixArtists() {
 919                         remixArtistsMemoizer.get();
 920                         return super.getRemixArtists();
 921                 }
 922
 923                 /**
 924                  * {@inheritDoc}
 925                  */
 926                 @Override
 927                 public Collection<TrackDerivative> getDerivatives() {
 928                         derivativesMemoizer.get();
 929                         return super.getDerivatives();
 930                 }
 931
 932                 /**
 933                  * {@inheritDoc}
 934                  */
 935                 @Override
 936                 public Map<Relationship, Collection<Track>> getRelatedTracks() {
 937                         relatedTracksMemoizer.get();
 938                         return super.getRelatedTracks();
 939                 }
 940
 941         }
 942
 943         /**
 944          * {@link ObjectCreator} implementation that can create {@link Track}
 945          * objects. This specific implementation creates {@link LazyTrack}
 946          * instances.
 947          *
 948          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 949          */
 950         private class TrackCreator implements ObjectCreator<Track> {
 951
 952                 /**
 953                  * {@inheritDoc}
 954                  */
 955                 @Override
 956                 public Track createObject(ResultSet resultSet) throws SQLException {
 957                         return new LazyTrack(resultSet.getString("TRACKS.ID")).setName(resultSet.getString("TRACKS.NAME")).setRemix(resultSet.getString("TRACKS.REMIX"));
 958                 }
 959
 960         }
 961
 962         /**
 963          * {@link ObjectCreator} implementation that can create
 964          * {@link TrackDerivative} objects.
 965          *
 966          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 967          */
 968         private class TrackDerivativeCreator implements ObjectCreator<TrackDerivative> {
 969
 970                 /**
 971                  * {@inheritDoc}
 972                  */
 973                 @Override
 974                 public TrackDerivative createObject(ResultSet resultSet) throws SQLException {
 975                         return new DefaultTrackDerivative(resultSet.getString("TRACK_DERIVATIVES.ID"));
 976                 }
 977
 978         }
 979
 980         /**
 981          * {@link ObjectCreator} implementation that can create {@link Style}
 982          * objects.
 983          *
 984          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 985          */
 986         private class StyleCreator implements ObjectCreator<Style> {
 987
 988                 /**
 989                  * {@inheritDoc}
 990                  */
 991                 @Override
 992                 public Style createObject(ResultSet resultSet) throws SQLException {
 993                         return new DefaultStyle(resultSet.getString("STYLES.ID")).setName(resultSet.getString("STYLES.NAME"));
 994                 }
 995
 996         }
 997
 998         /**
 999          * {@link User} implementation that retrieves some attributes (such as
1000          * {@link #getOpenIds()}) from the {@link DataManager} on demand.
1001          *
1002          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1003          */
1004         private class LazyUser extends DefaultUser {
1005
1006                 /** Memoizer for a user’s OpenIDs. */
1007                 private final Memoizer<Void> openIdMemoizer = new Memoizer<Void>(new Callable<Void>() {
1008
1009                         @Override
1010                         public Void call() throws Exception {
1011                                 if (!hasValue("openIds")) {
1012                                         getValue("openIds", Collection.class).set(getOpenIdsByUser(getId()));
1013                                 }
1014                                 return null;
1015                         }
1016                 });
1017
1018                 /**
1019                  * Creates a new user.
1020                  *
1021                  * @param id
1022                  *            The ID of the user
1023                  */
1024                 public LazyUser(String id) {
1025                         super(id);
1026                 }
1027
1028                 /**
1029                  * {@inheritDoc}
1030                  */
1031                 @Override
1032                 public Collection<String> getOpenIds() {
1033                         openIdMemoizer.get();
1034                         return super.getOpenIds();
1035                 }
1036
1037         }
1038
1039         /**
1040          * {@link ObjectCreator} implementation that can create {@link User}
1041          * objects. This specific implementation creates {@link LazyUser} instances.
1042          *
1043          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1044          */
1045         private class UserCreator implements ObjectCreator<User> {
1046
1047                 /**
1048                  * {@inheritDoc}
1049                  */
1050                 @Override
1051                 public User createObject(ResultSet resultSet) throws SQLException {
1052                         return new LazyUser(resultSet.getString("USERS.ID")).setName(resultSet.getString("USERS.NAME")).setPasswordHash(resultSet.getString("USERS.PASSWORD")).setLevel(resultSet.getInt("USERS.LEVEL"));
1053                 }
1054
1055         }
1056
1057 }