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 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 database.getMultiple(query, trackCreator);
 345         }
 346
 347         /**
 348          * Returns the derivative with the given ID.
 349          *
 350          * @param id
 351          *            The ID of the derivatives to load
 352          * @return The derivative with the given ID
 353          * @throws DatabaseException
 354          *             if a database error occurs
 355          */
 356         public TrackDerivative getTrackDerivativeById(String id) throws DatabaseException {
 357                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 358                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 359                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id))));
 360                 return loadTrackDerivativeProperties(database.getSingle(query, trackDerivativeCreator));
 361         }
 362
 363         /**
 364          * Returns the derivatives for the given track.
 365          *
 366          * @param track
 367          *            The track to get the derivatives for
 368          * @return The derivatives for the given track
 369          * @throws DatabaseException
 370          *             if a database error occurs
 371          */
 372         public Collection<TrackDerivative> getTrackDerivativesByTrack(Track track) throws DatabaseException {
 373                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
 374                 query.addField(new Field("TRACK_DERIVATIVES.*"));
 375                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(track.getId()))));
 376                 return loadTrackDerivativeProperties(database.getMultiple(query, trackDerivativeCreator));
 377         }
 378
 379         /**
 380          * Loads the properties for the given track derivative.
 381          *
 382          * @param trackDerivative
 383          *            The track derivative to load the properties for
 384          * @return The track derivative with its properties loaded
 385          * @throws DatabaseException
 386          *             if a database error occurs
 387          */
 388         public TrackDerivative loadTrackDerivativeProperties(TrackDerivative trackDerivative) throws DatabaseException {
 389                 return loadProperties(trackDerivative, "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE");
 390         }
 391
 392         /**
 393          * Loads the properties for the given track derivatives.
 394          *
 395          * @param trackDerivatives
 396          *            The track derivatives to load the properties for
 397          * @return The track derivatives with their properties loaded
 398          * @throws DatabaseException
 399          *             if a database error occurs
 400          */
 401         public List<TrackDerivative> loadTrackDerivativeProperties(List<TrackDerivative> trackDerivatives) throws DatabaseException {
 402                 for (TrackDerivative trackDerivative : trackDerivatives) {
 403                         loadTrackDerivativeProperties(trackDerivative);
 404                 }
 405                 return trackDerivatives;
 406         }
 407
 408         /**
 409          * Returns all groups the artist with the given ID belongs to.
 410          *
 411          * @param artistId
 412          *            The ID of the artist
 413          * @return All groups the artist belongs to
 414          * @throws DatabaseException
 415          *             if a database error occurs
 416          */
 417         public Collection<Group> getGroupsByArtist(String artistId) throws DatabaseException {
 418                 Query query = new Query(Type.SELECT, "GROUPS");
 419                 query.addField(new Field("GROUPS.*"));
 420                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("GROUPS.ID"), new Field("GROUP_ARTISTS.GROUP_")));
 421                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artistId))));
 422                 return database.getMultiple(query, groupCreator);
 423         }
 424
 425         /**
 426          * Returns all styles for the track with the given ID.
 427          *
 428          * @param trackId
 429          *            The ID of the track
 430          * @return All styles for the given track
 431          * @throws DatabaseException
 432          *             if a database error occurs
 433          */
 434         public Collection<Style> getStylesByTrack(String trackId) throws DatabaseException {
 435                 Query query = new Query(Type.SELECT, "STYLES");
 436                 query.addField(new Field("STYLES.*"));
 437                 query.addJoin(new Join(JoinType.INNER, "TRACK_STYLES", new Field("STYLES.ID"), new Field("TRACK_STYLES.STYLE")));
 438                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_STYLES.TRACK", new StringParameter(trackId))));
 439                 return database.getMultiple(query, styleCreator);
 440         }
 441
 442         /**
 443          * Returns the user with the given name.
 444          *
 445          * @param username
 446          *            The name of the user
 447          * @return The user, or {@code null} if the user does not exist
 448          * @throws DatabaseException
 449          *             if a database error occurs
 450          */
 451         public User getUserByName(String username) throws DatabaseException {
 452                 Query query = new Query(Type.SELECT, "USERS");
 453                 query.addField(new Field("USERS.*"));
 454                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USERS.NAME", new StringParameter(username))));
 455                 return database.getSingle(query, userCreator);
 456         }
 457
 458         /**
 459          * Returns the user connected with the given OpenID.
 460          *
 461          * @param openId
 462          *            The OpenID to find the user for
 463          * @return The user connected with the given OpenID, or {@code null} if
 464          *         there is no such user
 465          * @throws DatabaseException
 466          *             if a database error occurs
 467          */
 468         public User getUserByOpenId(String openId) throws DatabaseException {
 469                 Query query = new Query(Type.SELECT, "USERS");
 470                 query.addField(new Field("USERS.*"));
 471                 query.addJoin(new Join(JoinType.INNER, "USER_OPENIDS", new Field("USER_OPENIDS.USER"), new Field("USERS.ID")));
 472                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.OPENID", new StringParameter(openId))));
 473                 return database.getSingle(query, userCreator);
 474         }
 475
 476         /**
 477          * Returns all OpenIDs connected with the user with the given ID.
 478          *
 479          * @param userId
 480          *            The ID of the user
 481          * @return All OpenIDs connected with the given user
 482          * @throws DatabaseException
 483          *             if a database error occurs
 484          */
 485         public Collection<String> getOpenIdsByUser(String userId) throws DatabaseException {
 486                 Query query = new Query(Type.SELECT, "USER_OPENIDS");
 487                 query.addField(new Field("USER_OPENIDS.*"));
 488                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.USER", new StringParameter(userId))));
 489                 return database.getMultiple(query, new StringCreator("USER_OPENIDS.OPENID"));
 490         }
 491
 492         //
 493         // PRIVATE METHODS
 494         //
 495
 496         /**
 497          * Loads the properties for the given object.
 498          *
 499          * @param <T>
 500          *            The type of the object
 501          * @param object
 502          *            The object
 503          * @param table
 504          *            The table to load the properties from
 505          * @param type
 506          *            The type of the object (“ARTIST,” “TRACK,” etc.)
 507          * @return The object with its properties loaded
 508          * @throws DatabaseException
 509          *             if a database error occurs
 510          */
 511         private <T extends Base> T loadProperties(final T object, final String table, String type) throws DatabaseException {
 512                 Query query = new Query(Type.SELECT, table);
 513                 query.addField(new Field(table + ".PROPERTY"));
 514                 query.addField(new Field(table + ".VALUE"));
 515                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(object.getId()))));
 516                 database.process(query, new ResultProcessor() {
 517
 518                         @Override
 519                         public void processResult(ResultSet resultSet) throws SQLException {
 520                                 if (resultSet.isFirst()) {
 521                                         object.getProperties().removeAll();
 522                                 }
 523                                 object.getProperties().set(resultSet.getString(table + ".PROPERTY"), resultSet.getString(table + ".VALUE"));
 524                         }
 525
 526                 });
 527                 return object;
 528         }
 529
 530         /**
 531          * {@link Artist} implementation that retrieves some attributes (such as
 532          * {@link #getGroups()}, and {@link #getTracks()}) from the
 533          * {@link DataManager} on demand.
 534          *
 535          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 536          */
 537         private class LazyArtist extends DefaultArtist {
 538
 539                 /** Memoizer for the tracks by this artist. */
 540                 private final Memoizer<Void> tracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 541                         @Override
 542                         public Void call() throws DatabaseException {
 543                                 if (!hasValue("tracks")) {
 544                                         getValue("tracks", Collection.class).set(getTracksByArtist(getId()));
 545                                 }
 546                                 return null;
 547                         }
 548                 });
 549
 550                 /** Memoizer for the groups of this artist. */
 551                 private final Memoizer<Void> groupsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 552
 553                         @Override
 554                         public Void call() throws Exception {
 555                                 if (!hasValue("groups")) {
 556                                         getValue("groups", Collection.class).set(getGroupsByArtist(getId()));
 557                                 }
 558                                 return null;
 559                         }
 560
 561                 });
 562
 563                 /**
 564                  * Creates a new lazy artist.
 565                  *
 566                  * @param id
 567                  *            The ID of the artist
 568                  */
 569                 public LazyArtist(String id) {
 570                         super(id);
 571                 }
 572
 573                 //
 574                 // DEFAULTARTIST METHODS
 575                 //
 576
 577                 /**
 578                  * {@inheritDoc}
 579                  */
 580                 @Override
 581                 public Collection<Group> getGroups() {
 582                         groupsMemoizer.get();
 583                         return super.getGroups();
 584                 }
 585
 586                 /**
 587                  * {@inheritDoc}
 588                  */
 589                 @Override
 590                 public Collection<Track> getTracks() {
 591                         tracksMemoizer.get();
 592                         return super.getTracks();
 593                 }
 594
 595         }
 596
 597         /**
 598          * {@link ObjectCreator} implementation that can create {@link Artist}
 599          * objects. This specific class actually creates {@link LazyArtist}
 600          * instances.
 601          *
 602          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 603          */
 604         private class ArtistCreator implements ObjectCreator<Artist> {
 605
 606                 /**
 607                  * {@inheritDoc}
 608                  */
 609                 @Override
 610                 public Artist createObject(ResultSet resultSet) throws SQLException {
 611                         return new LazyArtist(resultSet.getString("ARTISTS.ID")).setName(resultSet.getString("ARTISTS.NAME"));
 612                 }
 613
 614         }
 615
 616         /**
 617          * {@link Group} implementation that retrieves some attributes (such as
 618          * {@link #getArtists()}) from the {@link DataManager} on demand.
 619          *
 620          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 621          */
 622         private class LazyGroup extends DefaultGroup {
 623
 624                 /** Memoizer for the artist. */
 625                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 626
 627                         @Override
 628                         public Void call() throws Exception {
 629                                 if (!hasValue("artists")) {
 630                                         getValue("artists", Collection.class).set(getArtistsByGroup(getId()));
 631                                 }
 632                                 return null;
 633                         }
 634
 635                 });
 636
 637                 /**
 638                  * Creates a new lazy group.
 639                  *
 640                  * @param id
 641                  *            The ID of the group
 642                  */
 643                 public LazyGroup(String id) {
 644                         super(id);
 645                 }
 646
 647                 //
 648                 // DEFAULTGROUP METHODS
 649                 //
 650
 651                 /**
 652                  * {@inheritDoc}
 653                  */
 654                 @Override
 655                 public Collection<Artist> getArtists() {
 656                         artistsMemoizer.get();
 657                         return super.getArtists();
 658                 }
 659
 660         }
 661
 662         /**
 663          * {@link ObjectCreator} implementation that can create {@link Group}
 664          * objects. This specific implementation creates {@link LazyGroup}
 665          * instances.
 666          *
 667          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 668          */
 669         private class GroupCreator implements ObjectCreator<Group> {
 670
 671                 /**
 672                  * {@inheritDoc}
 673                  */
 674                 @Override
 675                 public Group createObject(ResultSet resultSet) throws SQLException {
 676                         return new LazyGroup(resultSet.getString("GROUPS.ID")).setName(resultSet.getString("GROUPS.NAME")).setUrl(resultSet.getString("GROUPS.URL"));
 677                 }
 678
 679         }
 680
 681         /**
 682          * {@link Track} implementation that retrieves some attributes (such as
 683          * {@link #getArtists()}, and {@link #getStyles()}) from the
 684          * {@link DataManager} on demand.
 685          *
 686          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 687          */
 688         private class LazyTrack extends DefaultTrack {
 689
 690                 /** Memoizer for the artists. */
 691                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 692
 693                         @Override
 694                         public Void call() throws Exception {
 695                                 if (!hasValue("artists")) {
 696                                         getValue("artists", List.class).set(getArtistsByTrack(getId()));
 697                                 }
 698                                 return null;
 699                         }
 700
 701                 });
 702
 703                 /** Memoizer for the styles. */
 704                 private final Memoizer<Void> stylesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 705
 706                         @Override
 707                         public Void call() throws Exception {
 708                                 if (!hasValue("styles")) {
 709                                         getValue("styles", Collection.class).set(getStylesByTrack(getId()));
 710                                 }
 711                                 return null;
 712                         }
 713
 714                 });
 715
 716                 /** Memoizer for the remix artists. */
 717                 private final Memoizer<Void> remixArtistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 718
 719                         @Override
 720                         public Void call() throws Exception {
 721                                 if (!hasValue("remixArtists")) {
 722                                         getValue("remixArtists", List.class).set(getRemixArtistsByTrack(getId()));
 723                                 }
 724                                 return null;
 725                         }
 726
 727                 });
 728
 729                 /** Memoizer for the track derivatives. */
 730                 private final Memoizer<Void> derivativesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 731
 732                         @Override
 733                         public Void call() throws Exception {
 734                                 if (!hasValue("derivatives")) {
 735                                         getValue("derivatives", Collection.class).set(getTrackDerivativesByTrack(LazyTrack.this));
 736                                 }
 737                                 return null;
 738                         }
 739
 740                 });
 741
 742                 /** Memoizer for the related tracks. */
 743                 private final Memoizer<Void> relatedTracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 744
 745                         @Override
 746                         public Void call() throws Exception {
 747                                 if (!hasValue("relatedTracks")) {
 748                                         getValue("relatedTracks", Map.class).set(getRelatedTracksByTrack(getId()));
 749                                 }
 750                                 return null;
 751                         }
 752                 });
 753
 754                 /**
 755                  * Creates a new track.
 756                  *
 757                  * @param id
 758                  *            The ID of the track
 759                  */
 760                 public LazyTrack(String id) {
 761                         super(id);
 762                 }
 763
 764                 //
 765                 // DEFAULTTRACK METHODS
 766                 //
 767
 768                 /**
 769                  * {@inheritDoc}
 770                  */
 771                 @Override
 772                 public List<Artist> getArtists() {
 773                         artistsMemoizer.get();
 774                         return super.getArtists();
 775                 }
 776
 777                 /**
 778                  * {@inheritDoc}
 779                  */
 780                 @Override
 781                 public Collection<Style> getStyles() {
 782                         stylesMemoizer.get();
 783                         return super.getStyles();
 784                 }
 785
 786                 /**
 787                  * {@inheritDoc}
 788                  */
 789                 @Override
 790                 public List<Artist> getRemixArtists() {
 791                         remixArtistsMemoizer.get();
 792                         return super.getRemixArtists();
 793                 }
 794
 795                 /**
 796                  * {@inheritDoc}
 797                  */
 798                 @Override
 799                 public Collection<TrackDerivative> getDerivatives() {
 800                         derivativesMemoizer.get();
 801                         return super.getDerivatives();
 802                 }
 803
 804                 /**
 805                  * {@inheritDoc}
 806                  */
 807                 @Override
 808                 public Map<Relationship, Collection<Track>> getRelatedTracks() {
 809                         relatedTracksMemoizer.get();
 810                         return super.getRelatedTracks();
 811                 }
 812
 813         }
 814
 815         /**
 816          * {@link ObjectCreator} implementation that can create {@link Track}
 817          * objects. This specific implementation creates {@link LazyTrack}
 818          * instances.
 819          *
 820          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 821          */
 822         private class TrackCreator implements ObjectCreator<Track> {
 823
 824                 /**
 825                  * {@inheritDoc}
 826                  */
 827                 @Override
 828                 public Track createObject(ResultSet resultSet) throws SQLException {
 829                         return new LazyTrack(resultSet.getString("TRACKS.ID")).setName(resultSet.getString("TRACKS.NAME")).setRemix(resultSet.getString("TRACKS.REMIX"));
 830                 }
 831
 832         }
 833
 834         /**
 835          * {@link ObjectCreator} implementation that can create
 836          * {@link TrackDerivative} objects.
 837          *
 838          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 839          */
 840         private class TrackDerivativeCreator implements ObjectCreator<TrackDerivative> {
 841
 842                 /**
 843                  * {@inheritDoc}
 844                  */
 845                 @Override
 846                 public TrackDerivative createObject(ResultSet resultSet) throws SQLException {
 847                         return new DefaultTrackDerivative(resultSet.getString("TRACK_DERIVATIVES.ID"));
 848                 }
 849
 850         }
 851
 852         /**
 853          * {@link ObjectCreator} implementation that can create {@link Style}
 854          * objects.
 855          *
 856          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 857          */
 858         private class StyleCreator implements ObjectCreator<Style> {
 859
 860                 /**
 861                  * {@inheritDoc}
 862                  */
 863                 @Override
 864                 public Style createObject(ResultSet resultSet) throws SQLException {
 865                         return new DefaultStyle(resultSet.getString("STYLES.ID")).setName(resultSet.getString("STYLES.NAME"));
 866                 }
 867
 868         }
 869
 870         /**
 871          * {@link User} implementation that retrieves some attributes (such as
 872          * {@link #getOpenIds()}) from the {@link DataManager} on demand.
 873          *
 874          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 875          */
 876         private class LazyUser extends DefaultUser {
 877
 878                 /** Memoizer for a user’s OpenIDs. */
 879                 private final Memoizer<Void> openIdMemoizer = new Memoizer<Void>(new Callable<Void>() {
 880
 881                         @Override
 882                         public Void call() throws Exception {
 883                                 if (!hasValue("openIds")) {
 884                                         getValue("openIds", Collection.class).set(getOpenIdsByUser(getId()));
 885                                 }
 886                                 return null;
 887                         }
 888                 });
 889
 890                 /**
 891                  * Creates a new user.
 892                  *
 893                  * @param id
 894                  *            The ID of the user
 895                  */
 896                 public LazyUser(String id) {
 897                         super(id);
 898                 }
 899
 900                 /**
 901                  * {@inheritDoc}
 902                  */
 903                 @Override
 904                 public Collection<String> getOpenIds() {
 905                         openIdMemoizer.get();
 906                         return super.getOpenIds();
 907                 }
 908
 909         }
 910
 911         /**
 912          * {@link ObjectCreator} implementation that can create {@link User}
 913          * objects. This specific implementation creates {@link LazyUser} instances.
 914          *
 915          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 916          */
 917         private class UserCreator implements ObjectCreator<User> {
 918
 919                 /**
 920                  * {@inheritDoc}
 921                  */
 922                 @Override
 923                 public User createObject(ResultSet resultSet) throws SQLException {
 924                         return new LazyUser(resultSet.getString("USERS.ID")).setName(resultSet.getString("USERS.NAME")).setPasswordHash(resultSet.getString("USERS.PASSWORD")).setLevel(resultSet.getInt("USERS.LEVEL"));
 925                 }
 926
 927         }
 928
 929 }