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 loadProperties(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 loadProperties(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 loadProperties(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 loadProperties(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 loadProperties(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 loadProperties(final Artist artist) throws DatabaseException {
 244                 Query query = new Query(Type.SELECT, "ARTIST_PROPERTIES");
 245                 query.addField(new Field("ARTIST_PROPERTIES.PROPERTY"));
 246                 query.addField(new Field("ARTIST_PROPERTIES.VALUE"));
 247                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ARTIST", new StringParameter(artist.getId()))));
 248                 database.process(query, new ResultProcessor() {
 249
 250                         @Override
 251                         public void processResult(ResultSet resultSet) throws SQLException {
 252                                 if (resultSet.isFirst()) {
 253                                         artist.getProperties().removeAll();
 254                                 }
 255                                 artist.getProperties().set(resultSet.getString("ARTIST_PROPERTIES.PROPERTY"), resultSet.getString("ARTIST_PROPERTIES.VALUE"));
 256                         }
 257
 258                 });
 259                 return artist;
 260         }
 261
 262         /**
 263          * Loads the properties of all given artists.
 264          *
 265          * @param artists
 266          *            The artists to load the properties for
 267          * @return The list of artists
 268          * @throws DatabaseException
 269          *             if a database error occurs
 270          */
 271         public List<Artist> loadProperties(List<Artist> artists) throws DatabaseException {
 272                 for (Artist artist : artists) {
 273                         loadProperties(artist);
 274                 }
 275                 return artists;
 276         }
 277
 278         /**
 279          * Returns all remix artists involved in the track with the given ID.
 280          *
 281          * @param trackId
 282          *            The ID of the track
 283          * @return All remix artists involved in the track, in preferred order
 284          * @throws DatabaseException
 285          *             if a database error occurs
 286          */
 287         public List<Artist> getRemixArtistsByTrack(String trackId) throws DatabaseException {
 288                 Query query = new Query(Type.SELECT, "ARTISTS");
 289                 query.addField(new Field("ARTISTS.*"));
 290                 query.addJoin(new Join(JoinType.INNER, "TRACK_REMIX_ARTISTS", new Field("TRACK_REMIX_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 291                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_REMIX_ARTISTS.TRACK", new StringParameter(trackId))));
 292                 query.addOrderField(new OrderField(new Field("TRACK_REMIX_ARTISTS.DISPLAY_ORDER")));
 293                 return database.getMultiple(query, artistCreator);
 294         }
 295
 296         /**
 297          * Returns all related tracks for the track with the given ID.
 298          *
 299          * @param trackId
 300          *            The ID of the tracks
 301          * @return A mapping from relationship to all tracks that match the relation
 302          * @throws DatabaseException
 303          *             if a database error occurs
 304          */
 305         public Map<Relationship, Collection<Track>> getRelatedTracksByTrack(String trackId) throws DatabaseException {
 306                 Query query = new Query(Type.SELECT, "TRACKS");
 307                 query.addField(new Field("TRACKS.*"));
 308                 query.addField(new Field("TRACK_RELATIONS.*"));
 309                 query.addJoin(new Join(JoinType.INNER, "TRACK_RELATIONS", new Field("TRACK_RELATIONS.TRACK"), new Field("TRACK_RELATIONS.RELATED_TRACK")));
 310                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_RELATIONS.TRACK", new StringParameter(trackId))));
 311                 final Map<Relationship, Collection<Track>> relatedTracks = new EnumMap<Relationship, Collection<Track>>(Relationship.class);
 312                 database.process(query, new ResultProcessor() {
 313
 314                         @Override
 315                         @SuppressWarnings("synthetic-access")
 316                         public void processResult(ResultSet resultSet) throws SQLException {
 317                                 Track track = trackCreator.createObject(resultSet);
 318                                 Relationship relationship = Relationship.valueOf(resultSet.getString("TRACK_RELATIONS.RELATIONSHIP"));
 319                                 if (!relatedTracks.containsKey(relationship)) {
 320                                         relatedTracks.put(relationship, new HashSet<Track>());
 321                                 }
 322                                 relatedTracks.get(relationship).add(track);
 323                         }
 324                 });
 325                 return relatedTracks;
 326         }
 327
 328         /**
 329          * Returns the track with the given ID.
 330          *
 331          * @param id
 332          *            The ID of the track
 333          * @return The track with the given ID, or {@code null} if there is no such
 334          *         track
 335          * @throws DatabaseException
 336          *             if a database error occurs
 337          */
 338         public Track getTrackById(String id) throws DatabaseException {
 339                 Query query = new Query(Type.SELECT, "TRACKS");
 340                 query.addField(new Field("TRACKS.*"));
 341                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(id))));
 342                 return database.getSingle(query, trackCreator);
 343         }
 344
 345         /**
 346          * Returns all tracks by the artist with the given ID.
 347          *
 348          * @param artistId
 349          *            The ID of the artist
 350          * @return All tracks by the given artist
 351          * @throws DatabaseException
 352          *             if a database error occurs
 353          */
 354         public Collection<Track> getTracksByArtist(String artistId) throws DatabaseException {
 355                 Query query = new Query(Type.SELECT, "TRACKS");
 356                 query.addField(new Field("TRACKS.*"));
 357                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACKS.ID"), new Field("TRACK_ARTISTS.TRACK")));
 358                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(artistId))));
 359                 return database.getMultiple(query, trackCreator);
 360         }
 361
 362         /**
 363          * Returns all groups the artist with the given ID belongs to.
 364          *
 365          * @param artistId
 366          *            The ID of the artist
 367          * @return All groups the artist belongs to
 368          * @throws DatabaseException
 369          *             if a database error occurs
 370          */
 371         public Collection<Group> getGroupsByArtist(String artistId) throws DatabaseException {
 372                 Query query = new Query(Type.SELECT, "GROUPS");
 373                 query.addField(new Field("GROUPS.*"));
 374                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("GROUPS.ID"), new Field("GROUP_ARTISTS.GROUP_")));
 375                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artistId))));
 376                 return database.getMultiple(query, groupCreator);
 377         }
 378
 379         /**
 380          * Returns all styles for the track with the given ID.
 381          *
 382          * @param trackId
 383          *            The ID of the track
 384          * @return All styles for the given track
 385          * @throws DatabaseException
 386          *             if a database error occurs
 387          */
 388         public Collection<Style> getStylesByTrack(String trackId) throws DatabaseException {
 389                 Query query = new Query(Type.SELECT, "STYLES");
 390                 query.addField(new Field("STYLES.*"));
 391                 query.addJoin(new Join(JoinType.INNER, "TRACK_STYLES", new Field("STYLES.ID"), new Field("TRACK_STYLES.STYLE")));
 392                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_STYLES.TRACK", new StringParameter(trackId))));
 393                 return database.getMultiple(query, styleCreator);
 394         }
 395
 396         /**
 397          * Returns the user with the given name.
 398          *
 399          * @param username
 400          *            The name of the user
 401          * @return The user, or {@code null} if the user does not exist
 402          * @throws DatabaseException
 403          *             if a database error occurs
 404          */
 405         public User getUserByName(String username) throws DatabaseException {
 406                 Query query = new Query(Type.SELECT, "USERS");
 407                 query.addField(new Field("USERS.*"));
 408                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USERS.NAME", new StringParameter(username))));
 409                 return database.getSingle(query, userCreator);
 410         }
 411
 412         /**
 413          * Returns the user connected with the given OpenID.
 414          *
 415          * @param openId
 416          *            The OpenID to find the user for
 417          * @return The user connected with the given OpenID, or {@code null} if
 418          *         there is no such user
 419          * @throws DatabaseException
 420          *             if a database error occurs
 421          */
 422         public User getUserByOpenId(String openId) throws DatabaseException {
 423                 Query query = new Query(Type.SELECT, "USERS");
 424                 query.addField(new Field("USERS.*"));
 425                 query.addJoin(new Join(JoinType.INNER, "USER_OPENIDS", new Field("USER_OPENIDS.USER"), new Field("USERS.ID")));
 426                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.OPENID", new StringParameter(openId))));
 427                 return database.getSingle(query, userCreator);
 428         }
 429
 430         /**
 431          * Returns all OpenIDs connected with the user with the given ID.
 432          *
 433          * @param userId
 434          *            The ID of the user
 435          * @return All OpenIDs connected with the given user
 436          * @throws DatabaseException
 437          *             if a database error occurs
 438          */
 439         public Collection<String> getOpenIdsByUser(String userId) throws DatabaseException {
 440                 Query query = new Query(Type.SELECT, "USER_OPENIDS");
 441                 query.addField(new Field("USER_OPENIDS.*"));
 442                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.USER", new StringParameter(userId))));
 443                 return database.getMultiple(query, new StringCreator("USER_OPENIDS.OPENID"));
 444         }
 445
 446         /**
 447          * {@link Artist} implementation that retrieves some attributes (such as
 448          * {@link #getGroups()}, and {@link #getTracks()}) from the
 449          * {@link DataManager} on demand.
 450          *
 451          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 452          */
 453         private class LazyArtist extends DefaultArtist {
 454
 455                 /** Memoizer for the tracks by this artist. */
 456                 private final Memoizer<Void> tracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 457                         @Override
 458                         public Void call() throws DatabaseException {
 459                                 if (!hasValue("tracks")) {
 460                                         getValue("tracks", Collection.class).set(getTracksByArtist(getId()));
 461                                 }
 462                                 return null;
 463                         }
 464                 });
 465
 466                 /** Memoizer for the groups of this artist. */
 467                 private final Memoizer<Void> groupsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 468
 469                         @Override
 470                         public Void call() throws Exception {
 471                                 if (!hasValue("groups")) {
 472                                         getValue("groups", Collection.class).set(getGroupsByArtist(getId()));
 473                                 }
 474                                 return null;
 475                         }
 476
 477                 });
 478
 479                 /**
 480                  * Creates a new lazy artist.
 481                  *
 482                  * @param id
 483                  *            The ID of the artist
 484                  */
 485                 public LazyArtist(String id) {
 486                         super(id);
 487                 }
 488
 489                 //
 490                 // DEFAULTARTIST METHODS
 491                 //
 492
 493                 /**
 494                  * {@inheritDoc}
 495                  */
 496                 @Override
 497                 public Collection<Group> getGroups() {
 498                         groupsMemoizer.get();
 499                         return super.getGroups();
 500                 }
 501
 502                 /**
 503                  * {@inheritDoc}
 504                  */
 505                 @Override
 506                 public Collection<Track> getTracks() {
 507                         tracksMemoizer.get();
 508                         return super.getTracks();
 509                 }
 510
 511         }
 512
 513         /**
 514          * {@link ObjectCreator} implementation that can create {@link Artist}
 515          * objects. This specific class actually creates {@link LazyArtist}
 516          * instances.
 517          *
 518          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 519          */
 520         private class ArtistCreator implements ObjectCreator<Artist> {
 521
 522                 /**
 523                  * {@inheritDoc}
 524                  */
 525                 @Override
 526                 public Artist createObject(ResultSet resultSet) throws SQLException {
 527                         return new LazyArtist(resultSet.getString("ARTISTS.ID")).setName(resultSet.getString("ARTISTS.NAME"));
 528                 }
 529
 530         }
 531
 532         /**
 533          * {@link Group} implementation that retrieves some attributes (such as
 534          * {@link #getArtists()}) from the {@link DataManager} on demand.
 535          *
 536          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 537          */
 538         private class LazyGroup extends DefaultGroup {
 539
 540                 /** Memoizer for the artist. */
 541                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 542
 543                         @Override
 544                         public Void call() throws Exception {
 545                                 if (!hasValue("artists")) {
 546                                         getValue("artists", Collection.class).set(getArtistsByGroup(getId()));
 547                                 }
 548                                 return null;
 549                         }
 550
 551                 });
 552
 553                 /**
 554                  * Creates a new lazy group.
 555                  *
 556                  * @param id
 557                  *            The ID of the group
 558                  */
 559                 public LazyGroup(String id) {
 560                         super(id);
 561                 }
 562
 563                 //
 564                 // DEFAULTGROUP METHODS
 565                 //
 566
 567                 /**
 568                  * {@inheritDoc}
 569                  */
 570                 @Override
 571                 public Collection<Artist> getArtists() {
 572                         artistsMemoizer.get();
 573                         return super.getArtists();
 574                 }
 575
 576         }
 577
 578         /**
 579          * {@link ObjectCreator} implementation that can create {@link Group}
 580          * objects. This specific implementation creates {@link LazyGroup}
 581          * instances.
 582          *
 583          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 584          */
 585         private class GroupCreator implements ObjectCreator<Group> {
 586
 587                 /**
 588                  * {@inheritDoc}
 589                  */
 590                 @Override
 591                 public Group createObject(ResultSet resultSet) throws SQLException {
 592                         return new LazyGroup(resultSet.getString("GROUPS.ID")).setName(resultSet.getString("GROUPS.NAME")).setUrl(resultSet.getString("GROUPS.URL"));
 593                 }
 594
 595         }
 596
 597         /**
 598          * {@link Track} implementation that retrieves some attributes (such as
 599          * {@link #getArtists()}, and {@link #getStyles()}) from the
 600          * {@link DataManager} on demand.
 601          *
 602          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 603          */
 604         private class LazyTrack extends DefaultTrack {
 605
 606                 /** Memoizer for the artists. */
 607                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 608
 609                         @Override
 610                         public Void call() throws Exception {
 611                                 if (!hasValue("artists")) {
 612                                         getValue("artists", List.class).set(getArtistsByTrack(getId()));
 613                                 }
 614                                 return null;
 615                         }
 616
 617                 });
 618
 619                 /** Memoizer for the styles. */
 620                 private final Memoizer<Void> stylesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 621
 622                         @Override
 623                         public Void call() throws Exception {
 624                                 if (!hasValue("styles")) {
 625                                         getValue("styles", Collection.class).set(getStylesByTrack(getId()));
 626                                 }
 627                                 return null;
 628                         }
 629
 630                 });
 631
 632                 /** Memoizer for the remix artists. */
 633                 private final Memoizer<Void> remixArtistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 634
 635                         @Override
 636                         public Void call() throws Exception {
 637                                 if (!hasValue("remixArtists")) {
 638                                         getValue("remixArtists", List.class).set(getRemixArtistsByTrack(getId()));
 639                                 }
 640                                 return null;
 641                         }
 642
 643                 });
 644
 645                 /** Memoizer for the related tracks. */
 646                 private final Memoizer<Void> relatedTracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 647
 648                         @Override
 649                         public Void call() throws Exception {
 650                                 if (!hasValue("relatedTracks")) {
 651                                         getValue("relatedTracks", Map.class).set(getRelatedTracksByTrack(getId()));
 652                                 }
 653                                 return null;
 654                         }
 655                 });
 656
 657                 /**
 658                  * Creates a new track.
 659                  *
 660                  * @param id
 661                  *            The ID of the track
 662                  */
 663                 public LazyTrack(String id) {
 664                         super(id);
 665                 }
 666
 667                 //
 668                 // DEFAULTTRACK METHODS
 669                 //
 670
 671                 /**
 672                  * {@inheritDoc}
 673                  */
 674                 @Override
 675                 public List<Artist> getArtists() {
 676                         artistsMemoizer.get();
 677                         return super.getArtists();
 678                 }
 679
 680                 /**
 681                  * {@inheritDoc}
 682                  */
 683                 @Override
 684                 public Collection<Style> getStyles() {
 685                         stylesMemoizer.get();
 686                         return super.getStyles();
 687                 }
 688
 689                 /**
 690                  * {@inheritDoc}
 691                  */
 692                 @Override
 693                 public List<Artist> getRemixArtists() {
 694                         remixArtistsMemoizer.get();
 695                         return super.getRemixArtists();
 696                 }
 697
 698                 /**
 699                  * {@inheritDoc}
 700                  */
 701                 @Override
 702                 public Map<Relationship, Collection<Track>> getRelatedTracks() {
 703                         relatedTracksMemoizer.get();
 704                         return super.getRelatedTracks();
 705                 }
 706
 707         }
 708
 709         /**
 710          * {@link ObjectCreator} implementation that can create {@link Track}
 711          * objects. This specific implementation creates {@link LazyTrack}
 712          * instances.
 713          *
 714          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 715          */
 716         private class TrackCreator implements ObjectCreator<Track> {
 717
 718                 /**
 719                  * {@inheritDoc}
 720                  */
 721                 @Override
 722                 public Track createObject(ResultSet resultSet) throws SQLException {
 723                         return new LazyTrack(resultSet.getString("TRACKS.ID")).setName(resultSet.getString("TRACKS.NAME")).setRemix(resultSet.getString("TRACKS.REMIX"));
 724                 }
 725
 726         }
 727
 728         /**
 729          * {@link ObjectCreator} implementation that can create
 730          * {@link TrackDerivative} objects.
 731          *
 732          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 733          */
 734         private class TrackDerivativeCreator implements ObjectCreator<TrackDerivative> {
 735
 736                 /**
 737                  * {@inheritDoc}
 738                  */
 739                 @Override
 740                 public TrackDerivative createObject(ResultSet resultSet) throws SQLException {
 741                         return new DefaultTrackDerivative(resultSet.getString("TRACK_DERIVATIVES.ID"));
 742                 }
 743
 744         }
 745
 746         /**
 747          * {@link ObjectCreator} implementation that can create {@link Style}
 748          * objects.
 749          *
 750          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 751          */
 752         private class StyleCreator implements ObjectCreator<Style> {
 753
 754                 /**
 755                  * {@inheritDoc}
 756                  */
 757                 @Override
 758                 public Style createObject(ResultSet resultSet) throws SQLException {
 759                         return new DefaultStyle(resultSet.getString("STYLES.ID")).setName(resultSet.getString("STYLES.NAME"));
 760                 }
 761
 762         }
 763
 764         /**
 765          * {@link User} implementation that retrieves some attributes (such as
 766          * {@link #getOpenIds()}) from the {@link DataManager} on demand.
 767          *
 768          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 769          */
 770         private class LazyUser extends DefaultUser {
 771
 772                 /** Memoizer for a user’s OpenIDs. */
 773                 private final Memoizer<Void> openIdMemoizer = new Memoizer<Void>(new Callable<Void>() {
 774
 775                         @Override
 776                         public Void call() throws Exception {
 777                                 if (!hasValue("openIds")) {
 778                                         getValue("openIds", Collection.class).set(getOpenIdsByUser(getId()));
 779                                 }
 780                                 return null;
 781                         }
 782                 });
 783
 784                 /**
 785                  * Creates a new user.
 786                  *
 787                  * @param id
 788                  *            The ID of the user
 789                  */
 790                 public LazyUser(String id) {
 791                         super(id);
 792                 }
 793
 794                 /**
 795                  * {@inheritDoc}
 796                  */
 797                 @Override
 798                 public Collection<String> getOpenIds() {
 799                         openIdMemoizer.get();
 800                         return super.getOpenIds();
 801                 }
 802
 803         }
 804
 805         /**
 806          * {@link ObjectCreator} implementation that can create {@link User}
 807          * objects. This specific implementation creates {@link LazyUser} instances.
 808          *
 809          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 810          */
 811         private class UserCreator implements ObjectCreator<User> {
 812
 813                 /**
 814                  * {@inheritDoc}
 815                  */
 816                 @Override
 817                 public User createObject(ResultSet resultSet) throws SQLException {
 818                         return new LazyUser(resultSet.getString("USERS.ID")).setName(resultSet.getString("USERS.NAME")).setPasswordHash(resultSet.getString("USERS.PASSWORD")).setLevel(resultSet.getInt("USERS.LEVEL"));
 819                 }
 820
 821         }
 822
 823 }