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          * Creates a new derivative for the given track.
 381          *
 382          * @param track
 383          *            The track to create the derivative for
 384          * @return The created derivative
 385          * @throws DatabaseException
 386          *             if a database error occurs
 387          */
 388         public TrackDerivative createTrackDerivative(Track track) throws DatabaseException {
 389                 Query query = new Query(Type.INSERT, "TRACK_DERIVATIVES");
 390                 String id = UUID.randomUUID().toString();
 391                 query.addValueField(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id)));
 392                 query.addValueField(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(track.getId())));
 393                 database.insert(query);
 394                 return getTrackDerivativeById(id);
 395         }
 396
 397         /**
 398          * Loads the properties for the given track derivative.
 399          *
 400          * @param trackDerivative
 401          *            The track derivative to load the properties for
 402          * @return The track derivative with its properties loaded
 403          * @throws DatabaseException
 404          *             if a database error occurs
 405          */
 406         public TrackDerivative loadTrackDerivativeProperties(TrackDerivative trackDerivative) throws DatabaseException {
 407                 return loadProperties(trackDerivative, "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE");
 408         }
 409
 410         /**
 411          * Loads the properties for the given track derivatives.
 412          *
 413          * @param trackDerivatives
 414          *            The track derivatives to load the properties for
 415          * @return The track derivatives with their properties loaded
 416          * @throws DatabaseException
 417          *             if a database error occurs
 418          */
 419         public List<TrackDerivative> loadTrackDerivativeProperties(List<TrackDerivative> trackDerivatives) throws DatabaseException {
 420                 for (TrackDerivative trackDerivative : trackDerivatives) {
 421                         loadTrackDerivativeProperties(trackDerivative);
 422                 }
 423                 return trackDerivatives;
 424         }
 425
 426         /**
 427          * Returns all groups the artist with the given ID belongs to.
 428          *
 429          * @param artistId
 430          *            The ID of the artist
 431          * @return All groups the artist belongs to
 432          * @throws DatabaseException
 433          *             if a database error occurs
 434          */
 435         public Collection<Group> getGroupsByArtist(String artistId) throws DatabaseException {
 436                 Query query = new Query(Type.SELECT, "GROUPS");
 437                 query.addField(new Field("GROUPS.*"));
 438                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("GROUPS.ID"), new Field("GROUP_ARTISTS.GROUP_")));
 439                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artistId))));
 440                 return database.getMultiple(query, groupCreator);
 441         }
 442
 443         /**
 444          * Returns all styles for the track with the given ID.
 445          *
 446          * @param trackId
 447          *            The ID of the track
 448          * @return All styles for the given track
 449          * @throws DatabaseException
 450          *             if a database error occurs
 451          */
 452         public Collection<Style> getStylesByTrack(String trackId) throws DatabaseException {
 453                 Query query = new Query(Type.SELECT, "STYLES");
 454                 query.addField(new Field("STYLES.*"));
 455                 query.addJoin(new Join(JoinType.INNER, "TRACK_STYLES", new Field("STYLES.ID"), new Field("TRACK_STYLES.STYLE")));
 456                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_STYLES.TRACK", new StringParameter(trackId))));
 457                 return database.getMultiple(query, styleCreator);
 458         }
 459
 460         /**
 461          * Returns the user with the given name.
 462          *
 463          * @param username
 464          *            The name of the user
 465          * @return The user, or {@code null} if the user does not exist
 466          * @throws DatabaseException
 467          *             if a database error occurs
 468          */
 469         public User getUserByName(String username) throws DatabaseException {
 470                 Query query = new Query(Type.SELECT, "USERS");
 471                 query.addField(new Field("USERS.*"));
 472                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USERS.NAME", new StringParameter(username))));
 473                 return database.getSingle(query, userCreator);
 474         }
 475
 476         /**
 477          * Returns the user connected with the given OpenID.
 478          *
 479          * @param openId
 480          *            The OpenID to find the user for
 481          * @return The user connected with the given OpenID, or {@code null} if
 482          *         there is no such user
 483          * @throws DatabaseException
 484          *             if a database error occurs
 485          */
 486         public User getUserByOpenId(String openId) throws DatabaseException {
 487                 Query query = new Query(Type.SELECT, "USERS");
 488                 query.addField(new Field("USERS.*"));
 489                 query.addJoin(new Join(JoinType.INNER, "USER_OPENIDS", new Field("USER_OPENIDS.USER"), new Field("USERS.ID")));
 490                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.OPENID", new StringParameter(openId))));
 491                 return database.getSingle(query, userCreator);
 492         }
 493
 494         /**
 495          * Returns all OpenIDs connected with the user with the given ID.
 496          *
 497          * @param userId
 498          *            The ID of the user
 499          * @return All OpenIDs connected with the given user
 500          * @throws DatabaseException
 501          *             if a database error occurs
 502          */
 503         public Collection<String> getOpenIdsByUser(String userId) throws DatabaseException {
 504                 Query query = new Query(Type.SELECT, "USER_OPENIDS");
 505                 query.addField(new Field("USER_OPENIDS.*"));
 506                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.USER", new StringParameter(userId))));
 507                 return database.getMultiple(query, new StringCreator("USER_OPENIDS.OPENID"));
 508         }
 509
 510         //
 511         // PRIVATE METHODS
 512         //
 513
 514         /**
 515          * Loads the properties for the given object.
 516          *
 517          * @param <T>
 518          *            The type of the object
 519          * @param object
 520          *            The object
 521          * @param table
 522          *            The table to load the properties from
 523          * @param type
 524          *            The type of the object (“ARTIST,” “TRACK,” etc.)
 525          * @return The object with its properties loaded
 526          * @throws DatabaseException
 527          *             if a database error occurs
 528          */
 529         private <T extends Base> T loadProperties(final T object, final String table, String type) throws DatabaseException {
 530                 Query query = new Query(Type.SELECT, table);
 531                 query.addField(new Field(table + ".PROPERTY"));
 532                 query.addField(new Field(table + ".VALUE"));
 533                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(object.getId()))));
 534                 database.process(query, new ResultProcessor() {
 535
 536                         @Override
 537                         public void processResult(ResultSet resultSet) throws SQLException {
 538                                 if (resultSet.isFirst()) {
 539                                         object.getProperties().removeAll();
 540                                 }
 541                                 object.getProperties().set(resultSet.getString(table + ".PROPERTY"), resultSet.getString(table + ".VALUE"));
 542                         }
 543
 544                 });
 545                 return object;
 546         }
 547
 548         /**
 549          * {@link Artist} implementation that retrieves some attributes (such as
 550          * {@link #getGroups()}, and {@link #getTracks()}) from the
 551          * {@link DataManager} on demand.
 552          *
 553          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 554          */
 555         private class LazyArtist extends DefaultArtist {
 556
 557                 /** Memoizer for the tracks by this artist. */
 558                 private final Memoizer<Void> tracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 559                         @Override
 560                         public Void call() throws DatabaseException {
 561                                 if (!hasValue("tracks")) {
 562                                         getValue("tracks", Collection.class).set(getTracksByArtist(getId()));
 563                                 }
 564                                 return null;
 565                         }
 566                 });
 567
 568                 /** Memoizer for the groups of this artist. */
 569                 private final Memoizer<Void> groupsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 570
 571                         @Override
 572                         public Void call() throws Exception {
 573                                 if (!hasValue("groups")) {
 574                                         getValue("groups", Collection.class).set(getGroupsByArtist(getId()));
 575                                 }
 576                                 return null;
 577                         }
 578
 579                 });
 580
 581                 /**
 582                  * Creates a new lazy artist.
 583                  *
 584                  * @param id
 585                  *            The ID of the artist
 586                  */
 587                 public LazyArtist(String id) {
 588                         super(id);
 589                 }
 590
 591                 //
 592                 // DEFAULTARTIST METHODS
 593                 //
 594
 595                 /**
 596                  * {@inheritDoc}
 597                  */
 598                 @Override
 599                 public Collection<Group> getGroups() {
 600                         groupsMemoizer.get();
 601                         return super.getGroups();
 602                 }
 603
 604                 /**
 605                  * {@inheritDoc}
 606                  */
 607                 @Override
 608                 public Collection<Track> getTracks() {
 609                         tracksMemoizer.get();
 610                         return super.getTracks();
 611                 }
 612
 613         }
 614
 615         /**
 616          * {@link ObjectCreator} implementation that can create {@link Artist}
 617          * objects. This specific class actually creates {@link LazyArtist}
 618          * instances.
 619          *
 620          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 621          */
 622         private class ArtistCreator implements ObjectCreator<Artist> {
 623
 624                 /**
 625                  * {@inheritDoc}
 626                  */
 627                 @Override
 628                 public Artist createObject(ResultSet resultSet) throws SQLException {
 629                         return new LazyArtist(resultSet.getString("ARTISTS.ID")).setName(resultSet.getString("ARTISTS.NAME"));
 630                 }
 631
 632         }
 633
 634         /**
 635          * {@link Group} implementation that retrieves some attributes (such as
 636          * {@link #getArtists()}) from the {@link DataManager} on demand.
 637          *
 638          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 639          */
 640         private class LazyGroup extends DefaultGroup {
 641
 642                 /** Memoizer for the artist. */
 643                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 644
 645                         @Override
 646                         public Void call() throws Exception {
 647                                 if (!hasValue("artists")) {
 648                                         getValue("artists", Collection.class).set(getArtistsByGroup(getId()));
 649                                 }
 650                                 return null;
 651                         }
 652
 653                 });
 654
 655                 /**
 656                  * Creates a new lazy group.
 657                  *
 658                  * @param id
 659                  *            The ID of the group
 660                  */
 661                 public LazyGroup(String id) {
 662                         super(id);
 663                 }
 664
 665                 //
 666                 // DEFAULTGROUP METHODS
 667                 //
 668
 669                 /**
 670                  * {@inheritDoc}
 671                  */
 672                 @Override
 673                 public Collection<Artist> getArtists() {
 674                         artistsMemoizer.get();
 675                         return super.getArtists();
 676                 }
 677
 678         }
 679
 680         /**
 681          * {@link ObjectCreator} implementation that can create {@link Group}
 682          * objects. This specific implementation creates {@link LazyGroup}
 683          * instances.
 684          *
 685          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 686          */
 687         private class GroupCreator implements ObjectCreator<Group> {
 688
 689                 /**
 690                  * {@inheritDoc}
 691                  */
 692                 @Override
 693                 public Group createObject(ResultSet resultSet) throws SQLException {
 694                         return new LazyGroup(resultSet.getString("GROUPS.ID")).setName(resultSet.getString("GROUPS.NAME")).setUrl(resultSet.getString("GROUPS.URL"));
 695                 }
 696
 697         }
 698
 699         /**
 700          * {@link Track} implementation that retrieves some attributes (such as
 701          * {@link #getArtists()}, and {@link #getStyles()}) from the
 702          * {@link DataManager} on demand.
 703          *
 704          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 705          */
 706         private class LazyTrack extends DefaultTrack {
 707
 708                 /** Memoizer for the artists. */
 709                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 710
 711                         @Override
 712                         public Void call() throws Exception {
 713                                 if (!hasValue("artists")) {
 714                                         getValue("artists", List.class).set(getArtistsByTrack(getId()));
 715                                 }
 716                                 return null;
 717                         }
 718
 719                 });
 720
 721                 /** Memoizer for the styles. */
 722                 private final Memoizer<Void> stylesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 723
 724                         @Override
 725                         public Void call() throws Exception {
 726                                 if (!hasValue("styles")) {
 727                                         getValue("styles", Collection.class).set(getStylesByTrack(getId()));
 728                                 }
 729                                 return null;
 730                         }
 731
 732                 });
 733
 734                 /** Memoizer for the remix artists. */
 735                 private final Memoizer<Void> remixArtistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 736
 737                         @Override
 738                         public Void call() throws Exception {
 739                                 if (!hasValue("remixArtists")) {
 740                                         getValue("remixArtists", List.class).set(getRemixArtistsByTrack(getId()));
 741                                 }
 742                                 return null;
 743                         }
 744
 745                 });
 746
 747                 /** Memoizer for the track derivatives. */
 748                 private final Memoizer<Void> derivativesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 749
 750                         @Override
 751                         public Void call() throws Exception {
 752                                 if (!hasValue("derivatives")) {
 753                                         getValue("derivatives", Collection.class).set(getTrackDerivativesByTrack(LazyTrack.this));
 754                                 }
 755                                 return null;
 756                         }
 757
 758                 });
 759
 760                 /** Memoizer for the related tracks. */
 761                 private final Memoizer<Void> relatedTracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 762
 763                         @Override
 764                         public Void call() throws Exception {
 765                                 if (!hasValue("relatedTracks")) {
 766                                         getValue("relatedTracks", Map.class).set(getRelatedTracksByTrack(getId()));
 767                                 }
 768                                 return null;
 769                         }
 770                 });
 771
 772                 /**
 773                  * Creates a new track.
 774                  *
 775                  * @param id
 776                  *            The ID of the track
 777                  */
 778                 public LazyTrack(String id) {
 779                         super(id);
 780                 }
 781
 782                 //
 783                 // DEFAULTTRACK METHODS
 784                 //
 785
 786                 /**
 787                  * {@inheritDoc}
 788                  */
 789                 @Override
 790                 public List<Artist> getArtists() {
 791                         artistsMemoizer.get();
 792                         return super.getArtists();
 793                 }
 794
 795                 /**
 796                  * {@inheritDoc}
 797                  */
 798                 @Override
 799                 public Collection<Style> getStyles() {
 800                         stylesMemoizer.get();
 801                         return super.getStyles();
 802                 }
 803
 804                 /**
 805                  * {@inheritDoc}
 806                  */
 807                 @Override
 808                 public List<Artist> getRemixArtists() {
 809                         remixArtistsMemoizer.get();
 810                         return super.getRemixArtists();
 811                 }
 812
 813                 /**
 814                  * {@inheritDoc}
 815                  */
 816                 @Override
 817                 public Collection<TrackDerivative> getDerivatives() {
 818                         derivativesMemoizer.get();
 819                         return super.getDerivatives();
 820                 }
 821
 822                 /**
 823                  * {@inheritDoc}
 824                  */
 825                 @Override
 826                 public Map<Relationship, Collection<Track>> getRelatedTracks() {
 827                         relatedTracksMemoizer.get();
 828                         return super.getRelatedTracks();
 829                 }
 830
 831         }
 832
 833         /**
 834          * {@link ObjectCreator} implementation that can create {@link Track}
 835          * objects. This specific implementation creates {@link LazyTrack}
 836          * instances.
 837          *
 838          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 839          */
 840         private class TrackCreator implements ObjectCreator<Track> {
 841
 842                 /**
 843                  * {@inheritDoc}
 844                  */
 845                 @Override
 846                 public Track createObject(ResultSet resultSet) throws SQLException {
 847                         return new LazyTrack(resultSet.getString("TRACKS.ID")).setName(resultSet.getString("TRACKS.NAME")).setRemix(resultSet.getString("TRACKS.REMIX"));
 848                 }
 849
 850         }
 851
 852         /**
 853          * {@link ObjectCreator} implementation that can create
 854          * {@link TrackDerivative} objects.
 855          *
 856          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 857          */
 858         private class TrackDerivativeCreator implements ObjectCreator<TrackDerivative> {
 859
 860                 /**
 861                  * {@inheritDoc}
 862                  */
 863                 @Override
 864                 public TrackDerivative createObject(ResultSet resultSet) throws SQLException {
 865                         return new DefaultTrackDerivative(resultSet.getString("TRACK_DERIVATIVES.ID"));
 866                 }
 867
 868         }
 869
 870         /**
 871          * {@link ObjectCreator} implementation that can create {@link Style}
 872          * objects.
 873          *
 874          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 875          */
 876         private class StyleCreator implements ObjectCreator<Style> {
 877
 878                 /**
 879                  * {@inheritDoc}
 880                  */
 881                 @Override
 882                 public Style createObject(ResultSet resultSet) throws SQLException {
 883                         return new DefaultStyle(resultSet.getString("STYLES.ID")).setName(resultSet.getString("STYLES.NAME"));
 884                 }
 885
 886         }
 887
 888         /**
 889          * {@link User} implementation that retrieves some attributes (such as
 890          * {@link #getOpenIds()}) from the {@link DataManager} on demand.
 891          *
 892          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 893          */
 894         private class LazyUser extends DefaultUser {
 895
 896                 /** Memoizer for a user’s OpenIDs. */
 897                 private final Memoizer<Void> openIdMemoizer = new Memoizer<Void>(new Callable<Void>() {
 898
 899                         @Override
 900                         public Void call() throws Exception {
 901                                 if (!hasValue("openIds")) {
 902                                         getValue("openIds", Collection.class).set(getOpenIdsByUser(getId()));
 903                                 }
 904                                 return null;
 905                         }
 906                 });
 907
 908                 /**
 909                  * Creates a new user.
 910                  *
 911                  * @param id
 912                  *            The ID of the user
 913                  */
 914                 public LazyUser(String id) {
 915                         super(id);
 916                 }
 917
 918                 /**
 919                  * {@inheritDoc}
 920                  */
 921                 @Override
 922                 public Collection<String> getOpenIds() {
 923                         openIdMemoizer.get();
 924                         return super.getOpenIds();
 925                 }
 926
 927         }
 928
 929         /**
 930          * {@link ObjectCreator} implementation that can create {@link User}
 931          * objects. This specific implementation creates {@link LazyUser} instances.
 932          *
 933          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 934          */
 935         private class UserCreator implements ObjectCreator<User> {
 936
 937                 /**
 938                  * {@inheritDoc}
 939                  */
 940                 @Override
 941                 public User createObject(ResultSet resultSet) throws SQLException {
 942                         return new LazyUser(resultSet.getString("USERS.ID")).setName(resultSet.getString("USERS.NAME")).setPasswordHash(resultSet.getString("USERS.PASSWORD")).setLevel(resultSet.getInt("USERS.LEVEL"));
 943                 }
 944
 945         }
 946
 947 }