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.concurrent.Callable;
  28
  29 import net.pterodactylus.demoscenemusic.data.Track.Relationship;
  30 import net.pterodactylus.util.collection.Memoizer;
  31 import net.pterodactylus.util.database.Database;
  32 import net.pterodactylus.util.database.DatabaseException;
  33 import net.pterodactylus.util.database.Field;
  34 import net.pterodactylus.util.database.Join;
  35 import net.pterodactylus.util.database.Join.JoinType;
  36 import net.pterodactylus.util.database.ObjectCreator;
  37 import net.pterodactylus.util.database.ObjectCreator.StringCreator;
  38 import net.pterodactylus.util.database.OrderField;
  39 import net.pterodactylus.util.database.Parameter.StringParameter;
  40 import net.pterodactylus.util.database.Query;
  41 import net.pterodactylus.util.database.Query.Type;
  42 import net.pterodactylus.util.database.ResultProcessor;
  43 import net.pterodactylus.util.database.ValueField;
  44 import net.pterodactylus.util.database.ValueFieldWhereClause;
  45
  46 /**
  47  * Interface between the database and the application.
  48  *
  49  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  50  */
  51 public class DataManager {
  52
  53         /** The artist object creator. */
  54         @SuppressWarnings("synthetic-access")
  55         private final ObjectCreator<Artist> artistCreator = new ArtistCreator();
  56
  57         /** The group object creator. */
  58         @SuppressWarnings("synthetic-access")
  59         private final ObjectCreator<Group> groupCreator = new GroupCreator();
  60
  61         /** The track object creator. */
  62         @SuppressWarnings("synthetic-access")
  63         private final ObjectCreator<Track> trackCreator = new TrackCreator();
  64
  65         /** The style object creator. */
  66         @SuppressWarnings("synthetic-access")
  67         private final ObjectCreator<Style> styleCreator = new StyleCreator();
  68
  69         /** The {@link User} object creator. */
  70         @SuppressWarnings("synthetic-access")
  71         private final ObjectCreator<User> userCreator = new UserCreator();
  72
  73         /** The database. */
  74         private final Database database;
  75
  76         /**
  77          * Creates a new data manager.
  78          *
  79          * @param database
  80          *            The database to operate on
  81          */
  82         public DataManager(Database database) {
  83                 this.database = database;
  84         }
  85
  86         /**
  87          * Returns all artists.
  88          *
  89          * @return All artists
  90          * @throws DatabaseException
  91          *             if a database error occurs
  92          */
  93         public Collection<Artist> getAllArtists() throws DatabaseException {
  94                 Query query = new Query(Type.SELECT, "ARTISTS");
  95                 query.addField(new Field("ARTISTS.*"));
  96                 return database.getMultiple(query, artistCreator);
  97         }
  98
  99         /**
 100          * Returns the artist with the given ID.
 101          *
 102          * @param id
 103          *            The ID of the artist
 104          * @return The artist with the given ID, or {@code null} if there is no
 105          *         artist with the given ID
 106          * @throws DatabaseException
 107          *             if a database error occurs
 108          */
 109         public Artist getArtistById(String id) throws DatabaseException {
 110                 Query query = new Query(Type.SELECT, "ARTISTS");
 111                 query.addField(new Field("ARTISTS.*"));
 112                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ARTISTS.ID", new StringParameter(id))));
 113                 return database.getSingle(query, artistCreator);
 114         }
 115
 116         /**
 117          * Returns all artists that belong to the group with the given ID.
 118          *
 119          * @param groupId
 120          *            The ID of the group
 121          * @return All artists belonging to the given group
 122          * @throws DatabaseException
 123          *             if a database error occurs
 124          */
 125         public Collection<Artist> getArtistsByGroup(String groupId) throws DatabaseException {
 126                 Query query = new Query(Type.SELECT, "ARTISTS");
 127                 query.addField(new Field("ARTISTS.*"));
 128                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("ARTISTS.ID"), new Field("GROUP_ARTISTS.ARTIST")));
 129                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.GROUP_", new StringParameter(groupId))));
 130                 return database.getMultiple(query, artistCreator);
 131         }
 132
 133         /**
 134          * Returns all artists involved in the track with the given ID.
 135          *
 136          * @param trackId
 137          *            The ID of the track
 138          * @return All artists involved in the track, in preferred order
 139          * @throws DatabaseException
 140          *             if a database error occurs
 141          */
 142         public List<Artist> getArtistsByTrack(String trackId) throws DatabaseException {
 143                 Query query = new Query(Type.SELECT, "ARTISTS");
 144                 query.addField(new Field("ARTISTS.*"));
 145                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACK_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 146                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(trackId))));
 147                 query.addOrderField(new OrderField(new Field("TRACK_ARTISTS.DISPLAY_ORDER")));
 148                 return database.getMultiple(query, artistCreator);
 149         }
 150
 151         /**
 152          * Returns all remix artists involved in the track with the given ID.
 153          *
 154          * @param trackId
 155          *            The ID of the track
 156          * @return All remix artists involved in the track, in preferred order
 157          * @throws DatabaseException
 158          *             if a database error occurs
 159          */
 160         public List<Artist> getRemixArtistsByTrack(String trackId) throws DatabaseException {
 161                 Query query = new Query(Type.SELECT, "ARTISTS");
 162                 query.addField(new Field("ARTISTS.*"));
 163                 query.addJoin(new Join(JoinType.INNER, "TRACK_REMIX_ARTISTS", new Field("TRACK_REMIX_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
 164                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_REMIX_ARTISTS.TRACK", new StringParameter(trackId))));
 165                 query.addOrderField(new OrderField(new Field("TRACK_REMIX_ARTISTS.DISPLAY_ORDER")));
 166                 return database.getMultiple(query, artistCreator);
 167         }
 168
 169         /**
 170          * Returns all related tracks for the track with the given ID.
 171          *
 172          * @param trackId
 173          *            The ID of the tracks
 174          * @return A mapping from relationship to all tracks that match the relation
 175          * @throws DatabaseException
 176          *             if a database error occurs
 177          */
 178         public Map<Relationship, Collection<Track>> getRelatedTracksByTrack(String trackId) throws DatabaseException {
 179                 Query query = new Query(Type.SELECT, "TRACKS");
 180                 query.addField(new Field("TRACKS.*"));
 181                 query.addField(new Field("TRACK_RELATIONS.*"));
 182                 query.addJoin(new Join(JoinType.INNER, "TRACK_RELATIONS", new Field("TRACK_RELATIONS.TRACK"), new Field("TRACK_RELATIONS.RELATED_TRACK")));
 183                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_RELATIONS.TRACK", new StringParameter(trackId))));
 184                 final Map<Relationship, Collection<Track>> relatedTracks = new EnumMap<Relationship, Collection<Track>>(Relationship.class);
 185                 database.process(query, new ResultProcessor() {
 186
 187                         @Override
 188                         @SuppressWarnings("synthetic-access")
 189                         public void processResult(ResultSet resultSet) throws SQLException {
 190                                 Track track = trackCreator.createObject(resultSet);
 191                                 Relationship relationship = Relationship.valueOf(resultSet.getString("TRACK_RELATIONS.RELATIONSHIP"));
 192                                 if (!relatedTracks.containsKey(relationship)) {
 193                                         relatedTracks.put(relationship, new HashSet<Track>());
 194                                 }
 195                                 relatedTracks.get(relationship).add(track);
 196                         }
 197                 });
 198                 return relatedTracks;
 199         }
 200
 201         /**
 202          * Returns the track with the given ID.
 203          *
 204          * @param id
 205          *            The ID of the track
 206          * @return The track with the given ID, or {@code null} if there is no such
 207          *         track
 208          * @throws DatabaseException
 209          *             if a database error occurs
 210          */
 211         public Track getTrackById(String id) throws DatabaseException {
 212                 Query query = new Query(Type.SELECT, "TRACKS");
 213                 query.addField(new Field("TRACKS.*"));
 214                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(id))));
 215                 return database.getSingle(query, trackCreator);
 216         }
 217
 218         /**
 219          * Returns all tracks by the artist with the given ID.
 220          *
 221          * @param artistId
 222          *            The ID of the artist
 223          * @return All tracks by the given artist
 224          * @throws DatabaseException
 225          *             if a database error occurs
 226          */
 227         public Collection<Track> getTracksByArtist(String artistId) throws DatabaseException {
 228                 Query query = new Query(Type.SELECT, "TRACKS");
 229                 query.addField(new Field("TRACKS.*"));
 230                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACKS.ID"), new Field("TRACK_ARTISTS.TRACK")));
 231                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(artistId))));
 232                 return database.getMultiple(query, trackCreator);
 233         }
 234
 235         /**
 236          * Returns all groups the artist with the given ID belongs to.
 237          *
 238          * @param artistId
 239          *            The ID of the artist
 240          * @return All groups the artist belongs to
 241          * @throws DatabaseException
 242          *             if a database error occurs
 243          */
 244         public Collection<Group> getGroupsByArtist(String artistId) throws DatabaseException {
 245                 Query query = new Query(Type.SELECT, "GROUPS");
 246                 query.addField(new Field("GROUPS.*"));
 247                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("GROUPS.ID"), new Field("GROUP_ARTISTS.GROUP_")));
 248                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artistId))));
 249                 return database.getMultiple(query, groupCreator);
 250         }
 251
 252         /**
 253          * Returns all styles for the track with the given ID.
 254          *
 255          * @param trackId
 256          *            The ID of the track
 257          * @return All styles for the given track
 258          * @throws DatabaseException
 259          *             if a database error occurs
 260          */
 261         public Collection<Style> getStylesByTrack(String trackId) throws DatabaseException {
 262                 Query query = new Query(Type.SELECT, "STYLES");
 263                 query.addField(new Field("STYLES.*"));
 264                 query.addJoin(new Join(JoinType.INNER, "TRACK_STYLES", new Field("STYLES.ID"), new Field("TRACK_STYLES.STYLE")));
 265                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_STYLES.TRACK", new StringParameter(trackId))));
 266                 return database.getMultiple(query, styleCreator);
 267         }
 268
 269         /**
 270          * Returns the user with the given name.
 271          *
 272          * @param username
 273          *            The name of the user
 274          * @return The user, or {@code null} if the user does not exist
 275          * @throws DatabaseException
 276          *             if a database error occurs
 277          */
 278         public User getUserByName(String username) throws DatabaseException {
 279                 Query query = new Query(Type.SELECT, "USERS");
 280                 query.addField(new Field("USERS.*"));
 281                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USERS.NAME", new StringParameter(username))));
 282                 return database.getSingle(query, userCreator);
 283         }
 284
 285         /**
 286          * Returns the user connected with the given OpenID.
 287          *
 288          * @param openId
 289          *            The OpenID to find the user for
 290          * @return The user connected with the given OpenID, or {@code null} if
 291          *         there is no such user
 292          * @throws DatabaseException
 293          *             if a database error occurs
 294          */
 295         public User getUserByOpenId(String openId) throws DatabaseException {
 296                 Query query = new Query(Type.SELECT, "USERS");
 297                 query.addField(new Field("USERS.*"));
 298                 query.addJoin(new Join(JoinType.INNER, "USER_OPENIDS", new Field("USER_OPENIDS.USER"), new Field("USERS.ID")));
 299                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.OPENID", new StringParameter(openId))));
 300                 return database.getSingle(query, userCreator);
 301         }
 302
 303         /**
 304          * Returns all OpenIDs connected with the user with the given ID.
 305          *
 306          * @param userId
 307          *            The ID of the user
 308          * @return All OpenIDs connected with the given user
 309          * @throws DatabaseException
 310          *             if a database error occurs
 311          */
 312         public Collection<String> getOpenIdsByUser(String userId) throws DatabaseException {
 313                 Query query = new Query(Type.SELECT, "USER_OPENIDS");
 314                 query.addField(new Field("USER_OPENIDS.*"));
 315                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.USER", new StringParameter(userId))));
 316                 return database.getMultiple(query, new StringCreator("USER_OPENIDS.OPENID"));
 317         }
 318
 319         /**
 320          * {@link Artist} implementation that retrieves some attributes (such as
 321          * {@link #getGroups()}, and {@link #getTracks()}) from the
 322          * {@link DataManager} on demand.
 323          *
 324          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 325          */
 326         private class LazyArtist extends DefaultArtist {
 327
 328                 /** Memoizer for the tracks by this artist. */
 329                 private final Memoizer<Void> tracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 330                         @Override
 331                         public Void call() throws DatabaseException {
 332                                 if (!hasValue("tracks")) {
 333                                         getValue("tracks", Collection.class).set(getTracksByArtist(getId()));
 334                                 }
 335                                 return null;
 336                         }
 337                 });
 338
 339                 /** Memoizer for the groups of this artist. */
 340                 private final Memoizer<Void> groupsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 341
 342                         @Override
 343                         public Void call() throws Exception {
 344                                 if (!hasValue("groups")) {
 345                                         getValue("groups", Collection.class).set(getGroupsByArtist(getId()));
 346                                 }
 347                                 return null;
 348                         }
 349
 350                 });
 351
 352                 /**
 353                  * Creates a new lazy artist.
 354                  *
 355                  * @param id
 356                  *            The ID of the artist
 357                  */
 358                 public LazyArtist(String id) {
 359                         super(id);
 360                 }
 361
 362                 //
 363                 // DEFAULTARTIST METHODS
 364                 //
 365
 366                 /**
 367                  * {@inheritDoc}
 368                  */
 369                 @Override
 370                 public Collection<Group> getGroups() {
 371                         groupsMemoizer.get();
 372                         return super.getGroups();
 373                 }
 374
 375                 /**
 376                  * {@inheritDoc}
 377                  */
 378                 @Override
 379                 public Collection<Track> getTracks() {
 380                         tracksMemoizer.get();
 381                         return super.getTracks();
 382                 }
 383
 384         }
 385
 386         /**
 387          * {@link ObjectCreator} implementation that can create {@link Artist}
 388          * objects. This specific class actually creates {@link LazyArtist}
 389          * instances.
 390          *
 391          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 392          */
 393         private class ArtistCreator implements ObjectCreator<Artist> {
 394
 395                 /**
 396                  * {@inheritDoc}
 397                  */
 398                 @Override
 399                 public Artist createObject(ResultSet resultSet) throws SQLException {
 400                         return new LazyArtist(resultSet.getString("ARTISTS.ID")).setName(resultSet.getString("ARTISTS.NAME"));
 401                 }
 402
 403         }
 404
 405         /**
 406          * {@link Group} implementation that retrieves some attributes (such as
 407          * {@link #getArtists()}) from the {@link DataManager} on demand.
 408          *
 409          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 410          */
 411         private class LazyGroup extends DefaultGroup {
 412
 413                 /** Memoizer for the artist. */
 414                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 415
 416                         @Override
 417                         public Void call() throws Exception {
 418                                 if (!hasValue("artists")) {
 419                                         getValue("artists", Collection.class).set(getArtistsByGroup(getId()));
 420                                 }
 421                                 return null;
 422                         }
 423
 424                 });
 425
 426                 /**
 427                  * Creates a new lazy group.
 428                  *
 429                  * @param id
 430                  *            The ID of the group
 431                  */
 432                 public LazyGroup(String id) {
 433                         super(id);
 434                 }
 435
 436                 //
 437                 // DEFAULTGROUP METHODS
 438                 //
 439
 440                 /**
 441                  * {@inheritDoc}
 442                  */
 443                 @Override
 444                 public Collection<Artist> getArtists() {
 445                         artistsMemoizer.get();
 446                         return super.getArtists();
 447                 }
 448
 449         }
 450
 451         /**
 452          * {@link ObjectCreator} implementation that can create {@link Group}
 453          * objects. This specific implementation creates {@link LazyGroup}
 454          * instances.
 455          *
 456          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 457          */
 458         private class GroupCreator implements ObjectCreator<Group> {
 459
 460                 /**
 461                  * {@inheritDoc}
 462                  */
 463                 @Override
 464                 public Group createObject(ResultSet resultSet) throws SQLException {
 465                         return new LazyGroup(resultSet.getString("GROUPS.ID")).setName(resultSet.getString("GROUPS.NAME")).setUrl(resultSet.getString("GROUPS.URL"));
 466                 }
 467
 468         }
 469
 470         /**
 471          * {@link Track} implementation that retrieves some attributes (such as
 472          * {@link #getArtists()}, and {@link #getStyles()}) from the
 473          * {@link DataManager} on demand.
 474          *
 475          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 476          */
 477         private class LazyTrack extends DefaultTrack {
 478
 479                 /** Memoizer for the artists. */
 480                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 481
 482                         @Override
 483                         public Void call() throws Exception {
 484                                 if (!hasValue("artists")) {
 485                                         getValue("artists", List.class).set(getArtistsByTrack(getId()));
 486                                 }
 487                                 return null;
 488                         }
 489
 490                 });
 491
 492                 /** Memoizer for the styles. */
 493                 private final Memoizer<Void> stylesMemoizer = new Memoizer<Void>(new Callable<Void>() {
 494
 495                         @Override
 496                         public Void call() throws Exception {
 497                                 if (!hasValue("styles")) {
 498                                         getValue("styles", Collection.class).set(getStylesByTrack(getId()));
 499                                 }
 500                                 return null;
 501                         }
 502
 503                 });
 504
 505                 /** Memoizer for the remix artists. */
 506                 private final Memoizer<Void> remixArtistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
 507
 508                         @Override
 509                         public Void call() throws Exception {
 510                                 if (!hasValue("remixArtists")) {
 511                                         getValue("remixArtists", List.class).set(getRemixArtistsByTrack(getId()));
 512                                 }
 513                                 return null;
 514                         }
 515
 516                 });
 517
 518                 /** Memoizer for the related tracks. */
 519                 private final Memoizer<Void> relatedTracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
 520
 521                         @Override
 522                         public Void call() throws Exception {
 523                                 if (!hasValue("relatedTracks")) {
 524                                         getValue("relatedTracks", Map.class).set(getRelatedTracksByTrack(getId()));
 525                                 }
 526                                 return null;
 527                         }
 528                 });
 529
 530                 /**
 531                  * Creates a new track.
 532                  *
 533                  * @param id
 534                  *            The ID of the track
 535                  */
 536                 public LazyTrack(String id) {
 537                         super(id);
 538                 }
 539
 540                 //
 541                 // DEFAULTTRACK METHODS
 542                 //
 543
 544                 /**
 545                  * {@inheritDoc}
 546                  */
 547                 @Override
 548                 public List<Artist> getArtists() {
 549                         artistsMemoizer.get();
 550                         return super.getArtists();
 551                 }
 552
 553                 /**
 554                  * {@inheritDoc}
 555                  */
 556                 @Override
 557                 public Collection<Style> getStyles() {
 558                         stylesMemoizer.get();
 559                         return super.getStyles();
 560                 }
 561
 562                 /**
 563                  * {@inheritDoc}
 564                  */
 565                 @Override
 566                 public List<Artist> getRemixArtists() {
 567                         remixArtistsMemoizer.get();
 568                         return super.getRemixArtists();
 569                 }
 570
 571                 /**
 572                  * {@inheritDoc}
 573                  */
 574                 @Override
 575                 public Map<Relationship, Collection<Track>> getRelatedTracks() {
 576                         relatedTracksMemoizer.get();
 577                         return super.getRelatedTracks();
 578                 }
 579
 580         }
 581
 582         /**
 583          * {@link ObjectCreator} implementation that can create {@link Track}
 584          * objects. This specific implementation creates {@link LazyTrack}
 585          * instances.
 586          *
 587          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 588          */
 589         private class TrackCreator implements ObjectCreator<Track> {
 590
 591                 /**
 592                  * {@inheritDoc}
 593                  */
 594                 @Override
 595                 public Track createObject(ResultSet resultSet) throws SQLException {
 596                         return new LazyTrack(resultSet.getString("TRACKS.ID")).setName(resultSet.getString("TRACKS.NAME")).setRemix(resultSet.getString("TRACKS.REMIX"));
 597                 }
 598
 599         }
 600
 601         /**
 602          * {@link ObjectCreator} implementation that can create {@link Style}
 603          * objects.
 604          *
 605          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 606          */
 607         private class StyleCreator implements ObjectCreator<Style> {
 608
 609                 /**
 610                  * {@inheritDoc}
 611                  */
 612                 @Override
 613                 public Style createObject(ResultSet resultSet) throws SQLException {
 614                         return new DefaultStyle(resultSet.getString("STYLES.ID")).setName(resultSet.getString("STYLES.NAME"));
 615                 }
 616
 617         }
 618
 619         /**
 620          * {@link User} implementation that retrieves some attributes (such as
 621          * {@link #getOpenIds()}) from the {@link DataManager} on demand.
 622          *
 623          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 624          */
 625         private class LazyUser extends DefaultUser {
 626
 627                 /** Memoizer for a user’s OpenIDs. */
 628                 private final Memoizer<Void> openIdMemoizer = new Memoizer<Void>(new Callable<Void>() {
 629
 630                         @Override
 631                         public Void call() throws Exception {
 632                                 if (!hasValue("openIds")) {
 633                                         getValue("openIds", Collection.class).set(getOpenIdsByUser(getId()));
 634                                 }
 635                                 return null;
 636                         }
 637                 });
 638
 639                 /**
 640                  * Creates a new user.
 641                  *
 642                  * @param id
 643                  *            The ID of the user
 644                  */
 645                 public LazyUser(String id) {
 646                         super(id);
 647                 }
 648
 649                 /**
 650                  * {@inheritDoc}
 651                  */
 652                 @Override
 653                 public Collection<String> getOpenIds() {
 654                         openIdMemoizer.get();
 655                         return super.getOpenIds();
 656                 }
 657
 658         }
 659
 660         /**
 661          * {@link ObjectCreator} implementation that can create {@link User}
 662          * objects. This specific implementation creates {@link LazyUser} instances.
 663          *
 664          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 665          */
 666         private class UserCreator implements ObjectCreator<User> {
 667
 668                 /**
 669                  * {@inheritDoc}
 670                  */
 671                 @Override
 672                 public User createObject(ResultSet resultSet) throws SQLException {
 673                         return new LazyUser(resultSet.getString("USERS.ID")).setName(resultSet.getString("USERS.NAME")).setPasswordHash(resultSet.getString("USERS.PASSWORD")).setLevel(resultSet.getInt("USERS.LEVEL"));
 674                 }
 675
 676         }
 677
 678 }