Don’t load properties if there is no object.
[demoscenemusic.git] / src / main / java / net / pterodactylus / demoscenemusic / data / DataManager.java
1 /*
2  * DemosceneMusic - DataManager.java - Copyright © 2012 David Roden
3  *
4  * This program is free software: you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation, either version 3 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
16  */
17
18 package net.pterodactylus.demoscenemusic.data;
19
20 import java.sql.ResultSet;
21 import java.sql.SQLException;
22 import java.util.Collection;
23 import java.util.EnumMap;
24 import java.util.HashSet;
25 import java.util.List;
26 import java.util.Map;
27 import java.util.Map.Entry;
28 import java.util.UUID;
29 import java.util.concurrent.Callable;
30
31 import net.pterodactylus.demoscenemusic.data.Track.Relationship;
32 import net.pterodactylus.util.collection.Memoizer;
33 import net.pterodactylus.util.database.Database;
34 import net.pterodactylus.util.database.DatabaseException;
35 import net.pterodactylus.util.database.Field;
36 import net.pterodactylus.util.database.Join;
37 import net.pterodactylus.util.database.Join.JoinType;
38 import net.pterodactylus.util.database.ObjectCreator;
39 import net.pterodactylus.util.database.ObjectCreator.StringCreator;
40 import net.pterodactylus.util.database.OrderField;
41 import net.pterodactylus.util.database.Parameter.IntegerParameter;
42 import net.pterodactylus.util.database.Parameter.StringParameter;
43 import net.pterodactylus.util.database.Query;
44 import net.pterodactylus.util.database.Query.Type;
45 import net.pterodactylus.util.database.ResultProcessor;
46 import net.pterodactylus.util.database.ValueField;
47 import net.pterodactylus.util.database.ValueFieldWhereClause;
48
49 /**
50  * Interface between the database and the application.
51  *
52  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
53  */
54 public class DataManager {
55
56         /** The artist object creator. */
57         @SuppressWarnings("synthetic-access")
58         private final ObjectCreator<Artist> artistCreator = new ArtistCreator();
59
60         /** The group object creator. */
61         @SuppressWarnings("synthetic-access")
62         private final ObjectCreator<Group> groupCreator = new GroupCreator();
63
64         /** The track object creator. */
65         @SuppressWarnings("synthetic-access")
66         private final ObjectCreator<Track> trackCreator = new TrackCreator();
67
68         /** The track object creator. */
69         @SuppressWarnings("synthetic-access")
70         private final ObjectCreator<TrackDerivative> trackDerivativeCreator = new TrackDerivativeCreator();
71
72         /** The style object creator. */
73         @SuppressWarnings("synthetic-access")
74         private final ObjectCreator<Style> styleCreator = new StyleCreator();
75
76         /** The party object creator. */
77         @SuppressWarnings("synthetic-access")
78         private final ObjectCreator<Party> partyCreator = new PartyCreator();
79
80         /** The {@link User} object creator. */
81         @SuppressWarnings("synthetic-access")
82         private final ObjectCreator<User> userCreator = new UserCreator();
83
84         /** The database. */
85         private final Database database;
86
87         /**
88          * Creates a new data manager.
89          *
90          * @param database
91          *            The database to operate on
92          */
93         public DataManager(Database database) {
94                 this.database = database;
95         }
96
97         /**
98          * Returns all artists.
99          *
100          * @return All artists
101          * @throws DatabaseException
102          *             if a database error occurs
103          */
104         public Collection<Artist> getAllArtists() throws DatabaseException {
105                 Query query = new Query(Type.SELECT, "ARTISTS");
106                 query.addField(new Field("ARTISTS.*"));
107                 return loadArtistProperties(database.getMultiple(query, artistCreator));
108         }
109
110         /**
111          * Returns the artist with the given ID.
112          *
113          * @param id
114          *            The ID of the artist
115          * @return The artist with the given ID, or {@code null} if there is no
116          *         artist with the given ID
117          * @throws DatabaseException
118          *             if a database error occurs
119          */
120         public Artist getArtistById(String id) throws DatabaseException {
121                 Query query = new Query(Type.SELECT, "ARTISTS");
122                 query.addField(new Field("ARTISTS.*"));
123                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ARTISTS.ID", new StringParameter(id))));
124                 return loadArtistProperties(database.getSingle(query, artistCreator));
125         }
126
127         /**
128          * Returns all artists that belong to the group with the given ID.
129          *
130          * @param groupId
131          *            The ID of the group
132          * @return All artists belonging to the given group
133          * @throws DatabaseException
134          *             if a database error occurs
135          */
136         public Collection<Artist> getArtistsByGroup(String groupId) throws DatabaseException {
137                 Query query = new Query(Type.SELECT, "ARTISTS");
138                 query.addField(new Field("ARTISTS.*"));
139                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("ARTISTS.ID"), new Field("GROUP_ARTISTS.ARTIST")));
140                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.GROUP_", new StringParameter(groupId))));
141                 return loadArtistProperties(database.getMultiple(query, artistCreator));
142         }
143
144         /**
145          * Returns all artists involved in the track with the given ID.
146          *
147          * @param trackId
148          *            The ID of the track
149          * @return All artists involved in the track, in preferred order
150          * @throws DatabaseException
151          *             if a database error occurs
152          */
153         public List<Artist> getArtistsByTrack(String trackId) throws DatabaseException {
154                 Query query = new Query(Type.SELECT, "ARTISTS");
155                 query.addField(new Field("ARTISTS.*"));
156                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACK_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
157                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(trackId))));
158                 query.addOrderField(new OrderField(new Field("TRACK_ARTISTS.DISPLAY_ORDER")));
159                 return loadArtistProperties(database.getMultiple(query, artistCreator));
160         }
161
162         /**
163          * Creates a new artist with the given name.
164          *
165          * @param name
166          *            The name of the artist
167          * @return The created artist
168          * @throws DatabaseException
169          *             if a database error occurs
170          */
171         public Artist createArtist(String name) throws DatabaseException {
172                 Query query = new Query(Type.INSERT, "ARTISTS");
173                 String id = UUID.randomUUID().toString();
174                 query.addValueField(new ValueField("ID", new StringParameter(id)));
175                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
176                 database.insert(query);
177                 return loadArtistProperties(getArtistById(id));
178         }
179
180         /**
181          * Saves the given artist.
182          *
183          * @param artist
184          *            The artist to save
185          * @throws DatabaseException
186          *             if a database error occurs
187          */
188         public void saveArtist(Artist artist) throws DatabaseException {
189                 Query query = new Query(Type.UPDATE, "ARTISTS");
190                 query.addValueField(new ValueField("NAME", new StringParameter(artist.getName())));
191                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ID", new StringParameter(artist.getId()))));
192                 database.update(query);
193                 saveArtistProperties(artist);
194         }
195
196         /**
197          * Saves the properties of the given artist.
198          *
199          * @param artist
200          *            The artist whose properties to save
201          * @throws DatabaseException
202          *             if a database error occurs
203          */
204         public void saveArtistProperties(Artist artist) throws DatabaseException {
205                 saveProperties(artist.getProperties(), "ARTIST_PROPERTIES", "ARTIST", artist.getId());
206         }
207
208         /**
209          * Saves the given properties to the given table for the given principal.
210          *
211          * @param properties
212          *            The properties to save
213          * @param table
214          *            The table in which to save the properties
215          * @param type
216          *            The type of the principal (e. g. “ARTIST” or “TRACK”)
217          * @param id
218          *            The ID of the principial
219          * @throws DatabaseException
220          *             if a database error occurs
221          */
222         public void saveProperties(Properties properties, String table, String type, String id) throws DatabaseException {
223                 if (!properties.isDirty()) {
224                         return;
225                 }
226                 Query query = new Query(Type.DELETE, table);
227                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(id))));
228                 database.update(query);
229                 for (Entry<String, String> property : properties) {
230                         Query insertQuery = new Query(Type.INSERT, table);
231                         insertQuery.addValueField(new ValueField(type, new StringParameter(id)));
232                         insertQuery.addValueField(new ValueField("PROPERTY", new StringParameter(property.getKey())));
233                         insertQuery.addValueField(new ValueField("VALUE", new StringParameter(property.getValue())));
234                         database.insert(insertQuery);
235                 }
236                 properties.resetDirty();
237         }
238
239         /**
240          * Loads the properties for an artist.
241          *
242          * @param artist
243          *            The artist to load the properties for
244          * @return The artist
245          * @throws DatabaseException
246          *             if a database error occurs
247          */
248         public Artist loadArtistProperties(final Artist artist) throws DatabaseException {
249                 return loadProperties(artist, "ARTIST_PROPERTIES", "ARTIST");
250         }
251
252         /**
253          * Loads the properties of all given artists.
254          *
255          * @param artists
256          *            The artists to load the properties for
257          * @return The list of artists
258          * @throws DatabaseException
259          *             if a database error occurs
260          */
261         public List<Artist> loadArtistProperties(List<Artist> artists) throws DatabaseException {
262                 for (Artist artist : artists) {
263                         loadArtistProperties(artist);
264                 }
265                 return artists;
266         }
267
268         /**
269          * Returns all remix artists involved in the track with the given ID.
270          *
271          * @param trackId
272          *            The ID of the track
273          * @return All remix artists involved in the track, in preferred order
274          * @throws DatabaseException
275          *             if a database error occurs
276          */
277         public List<Artist> getRemixArtistsByTrack(String trackId) throws DatabaseException {
278                 Query query = new Query(Type.SELECT, "ARTISTS");
279                 query.addField(new Field("ARTISTS.*"));
280                 query.addJoin(new Join(JoinType.INNER, "TRACK_REMIX_ARTISTS", new Field("TRACK_REMIX_ARTISTS.ARTIST"), new Field("ARTISTS.ID")));
281                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_REMIX_ARTISTS.TRACK", new StringParameter(trackId))));
282                 query.addOrderField(new OrderField(new Field("TRACK_REMIX_ARTISTS.DISPLAY_ORDER")));
283                 return database.getMultiple(query, artistCreator);
284         }
285
286         /**
287          * Returns all related tracks for the track with the given ID.
288          *
289          * @param trackId
290          *            The ID of the tracks
291          * @return A mapping from relationship to all tracks that match the relation
292          * @throws DatabaseException
293          *             if a database error occurs
294          */
295         public Map<Relationship, Collection<Track>> getRelatedTracksByTrack(String trackId) throws DatabaseException {
296                 Query query = new Query(Type.SELECT, "TRACKS");
297                 query.addField(new Field("TRACKS.*"));
298                 query.addField(new Field("TRACK_RELATIONS.*"));
299                 query.addJoin(new Join(JoinType.INNER, "TRACK_RELATIONS", new Field("TRACK_RELATIONS.TRACK"), new Field("TRACK_RELATIONS.RELATED_TRACK")));
300                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_RELATIONS.TRACK", new StringParameter(trackId))));
301                 final Map<Relationship, Collection<Track>> relatedTracks = new EnumMap<Relationship, Collection<Track>>(Relationship.class);
302                 database.process(query, new ResultProcessor() {
303
304                         @Override
305                         @SuppressWarnings("synthetic-access")
306                         public void processResult(ResultSet resultSet) throws SQLException {
307                                 Track track = trackCreator.createObject(resultSet);
308                                 Relationship relationship = Relationship.valueOf(resultSet.getString("TRACK_RELATIONS.RELATIONSHIP"));
309                                 if (!relatedTracks.containsKey(relationship)) {
310                                         relatedTracks.put(relationship, new HashSet<Track>());
311                                 }
312                                 relatedTracks.get(relationship).add(track);
313                         }
314                 });
315                 return relatedTracks;
316         }
317
318         /**
319          * Returns the track with the given ID.
320          *
321          * @param id
322          *            The ID of the track
323          * @return The track with the given ID, or {@code null} if there is no such
324          *         track
325          * @throws DatabaseException
326          *             if a database error occurs
327          */
328         public Track getTrackById(String id) throws DatabaseException {
329                 Query query = new Query(Type.SELECT, "TRACKS");
330                 query.addField(new Field("TRACKS.*"));
331                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(id))));
332                 return loadTrackProperties(database.getSingle(query, trackCreator));
333         }
334
335         /**
336          * Returns the track that contains the derivative with the given ID.
337          *
338          * @param id
339          *            The ID of the track derivative
340          * @return The track the derivative belongs to, or {@code null} if there is
341          *         no such track
342          * @throws DatabaseException
343          *             if a database error occurs
344          */
345         public Track getTrackByDerivativeId(String id) throws DatabaseException {
346                 Query query = new Query(Type.SELECT, "TRACKS");
347                 query.addField(new Field("TRACKS.*"));
348                 query.addJoin(new Join(JoinType.INNER, "TRACK_DERIVATIVES", new Field("TRACK_DERIVATIVES.TRACK"), new Field("TRACKS.ID")));
349                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id))));
350                 return loadTrackProperties(database.getSingle(query, trackCreator));
351         }
352
353         /**
354          * Returns all tracks by the artist with the given ID.
355          *
356          * @param artistId
357          *            The ID of the artist
358          * @return All tracks by the given artist
359          * @throws DatabaseException
360          *             if a database error occurs
361          */
362         public Collection<Track> getTracksByArtist(String artistId) throws DatabaseException {
363                 Query query = new Query(Type.SELECT, "TRACKS");
364                 query.addField(new Field("TRACKS.*"));
365                 query.addJoin(new Join(JoinType.INNER, "TRACK_ARTISTS", new Field("TRACKS.ID"), new Field("TRACK_ARTISTS.TRACK")));
366                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(artistId))));
367                 return loadTrackProperties(database.getMultiple(query, trackCreator));
368         }
369
370         /**
371          * Returns all tracks that were released at the party with the given ID.
372          *
373          * @param partyId
374          *            The ID of the party
375          * @return All tracks that were released at the given party
376          * @throws DatabaseException
377          *             if a database error occurs
378          */
379         public Collection<Track> getTracksByParty(String partyId) throws DatabaseException {
380                 Query query = new Query(Type.SELECT, "TRACKS");
381                 query.addField(new Field("TRACKS.*"));
382                 query.addJoin(new Join(JoinType.INNER, "PARTY_TRACKS", new Field("PARTY_TRACKS.TRACK"), new Field("TRACKS.ID")));
383                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTY_TRACKS.PARTY", new StringParameter(partyId))));
384                 return loadTrackProperties(database.getMultiple(query, trackCreator));
385         }
386
387         /**
388          * Loads the properties for the given track.
389          *
390          * @param track
391          *            The track for which to load the properties
392          * @return The track with the properties loaded
393          * @throws DatabaseException
394          *             if a database error occurs
395          */
396         public Track loadTrackProperties(Track track) throws DatabaseException {
397                 return loadProperties(track, "TRACK_PROPERTIES", "TRACK");
398         }
399
400         /**
401          * Loads the properties for the given tracks.
402          *
403          * @param tracks
404          *            The tracks for which to load the properties
405          * @return The tracks with the properties loaded
406          * @throws DatabaseException
407          *             if a database error occurs
408          */
409         public List<Track> loadTrackProperties(List<Track> tracks) throws DatabaseException {
410                 for (Track track : tracks) {
411                         loadTrackProperties(track);
412                 }
413                 return tracks;
414         }
415
416         /**
417          * Creates a new track with the given name.
418          *
419          * @param name
420          *            The name of the track
421          * @return The created track
422          * @throws DatabaseException
423          *             if a database error occurs
424          */
425         public Track createTrack(String name) throws DatabaseException {
426                 Query query = new Query(Type.INSERT, "TRACKS");
427                 String id = UUID.randomUUID().toString();
428                 query.addValueField(new ValueField("ID", new StringParameter(id)));
429                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
430                 database.insert(query);
431                 return getTrackById(id);
432         }
433
434         /**
435          * Saves the given track. This also saves all relationships of the track.
436          *
437          * @param track
438          *            The track to save
439          * @throws DatabaseException
440          *             if a database error occurs
441          */
442         public void saveTrack(Track track) throws DatabaseException {
443                 Query query = new Query(Type.UPDATE, "TRACKS");
444                 query.addValueField(new ValueField("TRACKS.NAME", new StringParameter(track.getName())));
445                 query.addValueField(new ValueField("TRACKS.REMIX", new StringParameter(track.getRemix())));
446                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACKS.ID", new StringParameter(track.getId()))));
447                 database.update(query);
448                 /* store artist information. */
449                 track.getArtists(); /* prefetch artists. */
450                 query = new Query(Type.DELETE, "TRACK_ARTISTS");
451                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(track.getId()))));
452                 database.update(query);
453                 for (int index = 0; index < track.getArtists().size(); ++index) {
454                         query = new Query(Type.INSERT, "TRACK_ARTISTS");
455                         query.addValueField(new ValueField("TRACK_ARTISTS.TRACK", new StringParameter(track.getId())));
456                         query.addValueField(new ValueField("TRACK_ARTISTS.ARTIST", new StringParameter(track.getArtists().get(index).getId())));
457                         query.addValueField(new ValueField("TRACK_ARTISTS.DISPLAY_ORDER", new IntegerParameter(index + 1)));
458                         database.insert(query);
459                 }
460
461                 /* store party links. */
462                 Collection<Party> parties = track.getParties(); /* prefetch parties. */
463                 query = new Query(Type.DELETE, "PARTY_TRACKS");
464                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTY_TRACKS.TRACK", new StringParameter(track.getId()))));
465                 database.update(query);
466                 for (Party party : parties) {
467                         query = new Query(Type.INSERT, "PARTY_TRACKS");
468                         query.addValueField(new ValueField("PARTY_TRACKS.TRACK", new StringParameter(track.getId())));
469                         query.addValueField(new ValueField("PARTY_TRACKS.PARTY", new StringParameter(party.getId())));
470                         database.insert(query);
471                 }
472
473                 /* store properties. */
474                 saveProperties(track.getProperties(), "TRACK_PROPERTIES", "TRACK", track.getId());
475         }
476
477         /**
478          * Returns the derivative with the given ID.
479          *
480          * @param id
481          *            The ID of the derivatives to load
482          * @return The derivative with the given ID
483          * @throws DatabaseException
484          *             if a database error occurs
485          */
486         public TrackDerivative getTrackDerivativeById(String id) throws DatabaseException {
487                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
488                 query.addField(new Field("TRACK_DERIVATIVES.*"));
489                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id))));
490                 return loadTrackDerivativeProperties(database.getSingle(query, trackDerivativeCreator));
491         }
492
493         /**
494          * Returns the derivatives for the given track.
495          *
496          * @param trackId
497          *            The track ID to get the derivatives for
498          * @return The derivatives for the given track
499          * @throws DatabaseException
500          *             if a database error occurs
501          */
502         public Collection<TrackDerivative> getTrackDerivativesByTrack(String trackId) throws DatabaseException {
503                 Query query = new Query(Type.SELECT, "TRACK_DERIVATIVES");
504                 query.addField(new Field("TRACK_DERIVATIVES.*"));
505                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(trackId))));
506                 return loadTrackDerivativeProperties(database.getMultiple(query, trackDerivativeCreator));
507         }
508
509         /**
510          * Creates a new derivative for the given track.
511          *
512          * @param track
513          *            The track to create the derivative for
514          * @return The created derivative
515          * @throws DatabaseException
516          *             if a database error occurs
517          */
518         public TrackDerivative createTrackDerivative(Track track) throws DatabaseException {
519                 Query query = new Query(Type.INSERT, "TRACK_DERIVATIVES");
520                 String id = UUID.randomUUID().toString();
521                 query.addValueField(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(id)));
522                 query.addValueField(new ValueField("TRACK_DERIVATIVES.TRACK", new StringParameter(track.getId())));
523                 database.insert(query);
524                 return getTrackDerivativeById(id);
525         }
526
527         /**
528          * Loads the properties for the given track derivative.
529          *
530          * @param trackDerivative
531          *            The track derivative to load the properties for
532          * @return The track derivative with its properties loaded
533          * @throws DatabaseException
534          *             if a database error occurs
535          */
536         public TrackDerivative loadTrackDerivativeProperties(TrackDerivative trackDerivative) throws DatabaseException {
537                 return loadProperties(trackDerivative, "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE");
538         }
539
540         /**
541          * Loads the properties for the given track derivatives.
542          *
543          * @param trackDerivatives
544          *            The track derivatives to load the properties for
545          * @return The track derivatives with their properties loaded
546          * @throws DatabaseException
547          *             if a database error occurs
548          */
549         public List<TrackDerivative> loadTrackDerivativeProperties(List<TrackDerivative> trackDerivatives) throws DatabaseException {
550                 for (TrackDerivative trackDerivative : trackDerivatives) {
551                         loadTrackDerivativeProperties(trackDerivative);
552                 }
553                 return trackDerivatives;
554         }
555
556         /**
557          * Saves the given track derivative. As a track derivative does not have any
558          * attributes of its own only its properties are saved.
559          *
560          * @param trackDerivative
561          *            The track derivative to save
562          * @throws DatabaseException
563          *             if a database error occurs
564          */
565         public void saveTrackDerivate(TrackDerivative trackDerivative) throws DatabaseException {
566                 saveProperties(trackDerivative.getProperties(), "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE", trackDerivative.getId());
567         }
568
569         /**
570          * Removes the given track derivative and all its properties from the
571          * database.
572          *
573          * @param trackDerivative
574          *            The track derivative to remove
575          * @throws DatabaseException
576          *             if a database error occurs
577          */
578         public void removeTrackDerivative(TrackDerivative trackDerivative) throws DatabaseException {
579                 Query query = new Query(Type.DELETE, "TRACK_DERIVATIVES");
580                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_DERIVATIVES.ID", new StringParameter(trackDerivative.getId()))));
581                 database.update(query);
582                 /* remove the properties. */
583                 saveProperties(new Properties().set("dirty", "true").removeAll(), "TRACK_DERIVATIVE_PROPERTIES", "TRACK_DERIVATIVE", trackDerivative.getId());
584         }
585
586         /**
587          * Returns all groups the artist with the given ID belongs to.
588          *
589          * @param artistId
590          *            The ID of the artist
591          * @return All groups the artist belongs to
592          * @throws DatabaseException
593          *             if a database error occurs
594          */
595         public Collection<Group> getGroupsByArtist(String artistId) throws DatabaseException {
596                 Query query = new Query(Type.SELECT, "GROUPS");
597                 query.addField(new Field("GROUPS.*"));
598                 query.addJoin(new Join(JoinType.INNER, "GROUP_ARTISTS", new Field("GROUPS.ID"), new Field("GROUP_ARTISTS.GROUP_")));
599                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("GROUP_ARTISTS.ARTIST", new StringParameter(artistId))));
600                 return database.getMultiple(query, groupCreator);
601         }
602
603         /**
604          * Returns all styles for the track with the given ID.
605          *
606          * @param trackId
607          *            The ID of the track
608          * @return All styles for the given track
609          * @throws DatabaseException
610          *             if a database error occurs
611          */
612         public Collection<Style> getStylesByTrack(String trackId) throws DatabaseException {
613                 Query query = new Query(Type.SELECT, "STYLES");
614                 query.addField(new Field("STYLES.*"));
615                 query.addJoin(new Join(JoinType.INNER, "TRACK_STYLES", new Field("STYLES.ID"), new Field("TRACK_STYLES.STYLE")));
616                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("TRACK_STYLES.TRACK", new StringParameter(trackId))));
617                 return database.getMultiple(query, styleCreator);
618         }
619
620         /**
621          * Returns all parties.
622          *
623          * @return All parties
624          * @throws DatabaseException
625          *             if a database error occurs
626          */
627         public Collection<Party> getAllParties() throws DatabaseException {
628                 Query query = new Query(Type.SELECT, "PARTIES");
629                 query.addField(new Field("PARTIES.*"));
630                 return loadPartyProperties(database.getMultiple(query, partyCreator));
631         }
632
633         /**
634          * Returns all parties that the track with the given ID was released at.
635          *
636          * @param trackId
637          *            The ID of the track
638          * @return All parties the track was released at
639          * @throws DatabaseException
640          *             if a database error occurs
641          */
642         public Collection<Party> getPartiesByTrackId(String trackId) throws DatabaseException {
643                 Query query = new Query(Type.SELECT, "PARTIES");
644                 query.addField(new Field("PARTIES.*"));
645                 query.addJoin(new Join(JoinType.INNER, "PARTY_TRACKS", new Field("PARTY_TRACKS.PARTY"), new Field("PARTIES.ID")));
646                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTY_TRACKS.TRACK", new StringParameter(trackId))));
647                 return loadPartyProperties(database.getMultiple(query, partyCreator));
648         }
649
650         /**
651          * Returns the party with the given ID.
652          *
653          * @param partyId
654          *            The ID of the party
655          * @return The party with the given ID
656          * @throws DatabaseException
657          *             if a database error occurs
658          */
659         public Party getPartyById(String partyId) throws DatabaseException {
660                 Query query = new Query(Type.SELECT, "PARTIES");
661                 query.addField(new Field("PARTIES.*"));
662                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("PARTIES.ID", new StringParameter(partyId))));
663                 return loadPartyProperties(database.getSingle(query, partyCreator));
664         }
665
666         /**
667          * Loads the properties of the given party.
668          *
669          * @param party
670          *            The party to load the properties for
671          * @return The party with its properties loaded
672          * @throws DatabaseException
673          *             if a database error occurs
674          */
675         public Party loadPartyProperties(Party party) throws DatabaseException {
676                 return loadProperties(party, "PARTY_PROPERTIES", "PARTY");
677         }
678
679         /**
680          * Loads the properties of the given parties.
681          *
682          * @param parties
683          *            The parties to load the properties for
684          * @return The parties with their properties loaded
685          * @throws DatabaseException
686          *             if a database error occurs
687          */
688         public List<Party> loadPartyProperties(List<Party> parties) throws DatabaseException {
689                 for (Party party : parties) {
690                         loadPartyProperties(party);
691                 }
692                 return parties;
693         }
694
695         /**
696          * Saves the given party.
697          *
698          * @param party
699          *            The party to save
700          * @throws DatabaseException
701          *             if a database error occurs
702          */
703         public void saveParty(Party party) throws DatabaseException {
704                 Query query = new Query(Type.UPDATE, "PARTIES");
705                 query.addValueField(new ValueField("NAME", new StringParameter(party.getName())));
706                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("ID", new StringParameter(party.getId()))));
707                 database.update(query);
708                 savePartyProperties(party);
709         }
710
711         /**
712          * Saves the properties of the given party.
713          *
714          * @param party
715          *            The party whose properties to save
716          * @throws DatabaseException
717          *             if a database error occurs
718          */
719         public void savePartyProperties(Party party) throws DatabaseException {
720                 saveProperties(party.getProperties(), "PARTY_PROPERTIES", "PARTY", party.getId());
721         }
722
723         /**
724          * Creates a new party with the given name.
725          *
726          * @param name
727          *            The name of the party
728          * @return The new party
729          * @throws DatabaseException
730          *             if a database error occurs
731          */
732         public Party createParty(String name) throws DatabaseException {
733                 Query query = new Query(Type.INSERT, "PARTIES");
734                 String id = UUID.randomUUID().toString();
735                 query.addValueField(new ValueField("ID", new StringParameter(id)));
736                 query.addValueField(new ValueField("NAME", new StringParameter(name)));
737                 database.insert(query);
738                 return getPartyById(id);
739         }
740
741         /**
742          * Returns the user with the given name.
743          *
744          * @param username
745          *            The name of the user
746          * @return The user, or {@code null} if the user does not exist
747          * @throws DatabaseException
748          *             if a database error occurs
749          */
750         public User getUserByName(String username) throws DatabaseException {
751                 Query query = new Query(Type.SELECT, "USERS");
752                 query.addField(new Field("USERS.*"));
753                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USERS.NAME", new StringParameter(username))));
754                 return database.getSingle(query, userCreator);
755         }
756
757         /**
758          * Returns the user connected with the given OpenID.
759          *
760          * @param openId
761          *            The OpenID to find the user for
762          * @return The user connected with the given OpenID, or {@code null} if
763          *         there is no such user
764          * @throws DatabaseException
765          *             if a database error occurs
766          */
767         public User getUserByOpenId(String openId) throws DatabaseException {
768                 Query query = new Query(Type.SELECT, "USERS");
769                 query.addField(new Field("USERS.*"));
770                 query.addJoin(new Join(JoinType.INNER, "USER_OPENIDS", new Field("USER_OPENIDS.USER"), new Field("USERS.ID")));
771                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.OPENID", new StringParameter(openId))));
772                 return database.getSingle(query, userCreator);
773         }
774
775         /**
776          * Returns all OpenIDs connected with the user with the given ID.
777          *
778          * @param userId
779          *            The ID of the user
780          * @return All OpenIDs connected with the given user
781          * @throws DatabaseException
782          *             if a database error occurs
783          */
784         public Collection<String> getOpenIdsByUser(String userId) throws DatabaseException {
785                 Query query = new Query(Type.SELECT, "USER_OPENIDS");
786                 query.addField(new Field("USER_OPENIDS.*"));
787                 query.addWhereClause(new ValueFieldWhereClause(new ValueField("USER_OPENIDS.USER", new StringParameter(userId))));
788                 return database.getMultiple(query, new StringCreator("USER_OPENIDS.OPENID"));
789         }
790
791         //
792         // PRIVATE METHODS
793         //
794
795         /**
796          * Loads the properties for the given object.
797          *
798          * @param <T>
799          *            The type of the object
800          * @param object
801          *            The object
802          * @param table
803          *            The table to load the properties from
804          * @param type
805          *            The type of the object (“ARTIST,” “TRACK,” etc.)
806          * @return The object with its properties loaded
807          * @throws DatabaseException
808          *             if a database error occurs
809          */
810         private <T extends Base> T loadProperties(final T object, final String table, String type) throws DatabaseException {
811                 if (object == null) {
812                         return null;
813                 }
814                 Query query = new Query(Type.SELECT, table);
815                 query.addField(new Field(table + ".PROPERTY"));
816                 query.addField(new Field(table + ".VALUE"));
817                 query.addWhereClause(new ValueFieldWhereClause(new ValueField(type, new StringParameter(object.getId()))));
818                 database.process(query, new ResultProcessor() {
819
820                         @Override
821                         public void processResult(ResultSet resultSet) throws SQLException {
822                                 if (resultSet.isFirst()) {
823                                         object.getProperties().removeAll();
824                                 }
825                                 object.getProperties().set(resultSet.getString(table + ".PROPERTY"), resultSet.getString(table + ".VALUE"));
826                         }
827
828                 });
829                 return object;
830         }
831
832         /**
833          * {@link Artist} implementation that retrieves some attributes (such as
834          * {@link #getGroups()}, and {@link #getTracks()}) from the
835          * {@link DataManager} on demand.
836          *
837          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
838          */
839         private class LazyArtist extends DefaultArtist {
840
841                 /** Memoizer for the tracks by this artist. */
842                 private final Memoizer<Void> tracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
843
844                         @Override
845                         public Void call() throws DatabaseException {
846                                 if (!hasValue("tracks")) {
847                                         getValue("tracks", Collection.class).set(getTracksByArtist(getId()));
848                                 }
849                                 return null;
850                         }
851                 });
852
853                 /** Memoizer for the groups of this artist. */
854                 private final Memoizer<Void> groupsMemoizer = new Memoizer<Void>(new Callable<Void>() {
855
856                         @Override
857                         public Void call() throws Exception {
858                                 if (!hasValue("groups")) {
859                                         getValue("groups", Collection.class).set(getGroupsByArtist(getId()));
860                                 }
861                                 return null;
862                         }
863
864                 });
865
866                 /**
867                  * Creates a new lazy artist.
868                  *
869                  * @param id
870                  *            The ID of the artist
871                  */
872                 public LazyArtist(String id) {
873                         super(id);
874                 }
875
876                 //
877                 // DEFAULTARTIST METHODS
878                 //
879
880                 /**
881                  * {@inheritDoc}
882                  */
883                 @Override
884                 public Collection<Group> getGroups() {
885                         groupsMemoizer.get();
886                         return super.getGroups();
887                 }
888
889                 /**
890                  * {@inheritDoc}
891                  */
892                 @Override
893                 public Collection<Track> getTracks() {
894                         tracksMemoizer.get();
895                         return super.getTracks();
896                 }
897
898         }
899
900         /**
901          * {@link ObjectCreator} implementation that can create {@link Artist}
902          * objects. This specific class actually creates {@link LazyArtist}
903          * instances.
904          *
905          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
906          */
907         private class ArtistCreator implements ObjectCreator<Artist> {
908
909                 /**
910                  * {@inheritDoc}
911                  */
912                 @Override
913                 public Artist createObject(ResultSet resultSet) throws SQLException {
914                         return new LazyArtist(resultSet.getString("ARTISTS.ID")).setName(resultSet.getString("ARTISTS.NAME"));
915                 }
916
917         }
918
919         /**
920          * {@link Group} implementation that retrieves some attributes (such as
921          * {@link #getArtists()}) from the {@link DataManager} on demand.
922          *
923          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
924          */
925         private class LazyGroup extends DefaultGroup {
926
927                 /** Memoizer for the artist. */
928                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
929
930                         @Override
931                         public Void call() throws Exception {
932                                 if (!hasValue("artists")) {
933                                         getValue("artists", Collection.class).set(getArtistsByGroup(getId()));
934                                 }
935                                 return null;
936                         }
937
938                 });
939
940                 /**
941                  * Creates a new lazy group.
942                  *
943                  * @param id
944                  *            The ID of the group
945                  */
946                 public LazyGroup(String id) {
947                         super(id);
948                 }
949
950                 //
951                 // DEFAULTGROUP METHODS
952                 //
953
954                 /**
955                  * {@inheritDoc}
956                  */
957                 @Override
958                 public Collection<Artist> getArtists() {
959                         artistsMemoizer.get();
960                         return super.getArtists();
961                 }
962
963         }
964
965         /**
966          * {@link ObjectCreator} implementation that can create {@link Group}
967          * objects. This specific implementation creates {@link LazyGroup}
968          * instances.
969          *
970          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
971          */
972         private class GroupCreator implements ObjectCreator<Group> {
973
974                 /**
975                  * {@inheritDoc}
976                  */
977                 @Override
978                 public Group createObject(ResultSet resultSet) throws SQLException {
979                         return new LazyGroup(resultSet.getString("GROUPS.ID")).setName(resultSet.getString("GROUPS.NAME")).setUrl(resultSet.getString("GROUPS.URL"));
980                 }
981
982         }
983
984         /**
985          * {@link Track} implementation that retrieves some attributes (such as
986          * {@link #getArtists()}, and {@link #getStyles()}) from the
987          * {@link DataManager} on demand.
988          *
989          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
990          */
991         private class LazyTrack extends DefaultTrack {
992
993                 /** Memoizer for the artists. */
994                 private final Memoizer<Void> artistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
995
996                         @Override
997                         public Void call() throws Exception {
998                                 if (!hasValue("artists")) {
999                                         getValue("artists", List.class).set(getArtistsByTrack(getId()));
1000                                 }
1001                                 return null;
1002                         }
1003
1004                 });
1005
1006                 /** Memoizer for the styles. */
1007                 private final Memoizer<Void> stylesMemoizer = new Memoizer<Void>(new Callable<Void>() {
1008
1009                         @Override
1010                         public Void call() throws Exception {
1011                                 if (!hasValue("styles")) {
1012                                         getValue("styles", Collection.class).set(getStylesByTrack(getId()));
1013                                 }
1014                                 return null;
1015                         }
1016
1017                 });
1018
1019                 /** Memoizer for the remix artists. */
1020                 private final Memoizer<Void> remixArtistsMemoizer = new Memoizer<Void>(new Callable<Void>() {
1021
1022                         @Override
1023                         public Void call() throws Exception {
1024                                 if (!hasValue("remixArtists")) {
1025                                         getValue("remixArtists", List.class).set(getRemixArtistsByTrack(getId()));
1026                                 }
1027                                 return null;
1028                         }
1029
1030                 });
1031
1032                 /** Memoizer for the track derivatives. */
1033                 private final Memoizer<Void> derivativesMemoizer = new Memoizer<Void>(new Callable<Void>() {
1034
1035                         @Override
1036                         public Void call() throws Exception {
1037                                 if (!hasValue("derivatives")) {
1038                                         getValue("derivatives", Collection.class).set(getTrackDerivativesByTrack(getId()));
1039                                 }
1040                                 return null;
1041                         }
1042
1043                 });
1044
1045                 /** Memoizer for the related tracks. */
1046                 private final Memoizer<Void> relatedTracksMemoizer = new Memoizer<Void>(new Callable<Void>() {
1047
1048                         @Override
1049                         public Void call() throws Exception {
1050                                 if (!hasValue("relatedTracks")) {
1051                                         getValue("relatedTracks", Map.class).set(getRelatedTracksByTrack(getId()));
1052                                 }
1053                                 return null;
1054                         }
1055
1056                 });
1057
1058                 /**
1059                  * Creates a new track.
1060                  *
1061                  * @param id
1062                  *            The ID of the track
1063                  */
1064                 public LazyTrack(String id) {
1065                         super(id);
1066                 }
1067
1068                 //
1069                 // DEFAULTTRACK METHODS
1070                 //
1071
1072                 /**
1073                  * {@inheritDoc}
1074                  */
1075                 @Override
1076                 public List<Artist> getArtists() {
1077                         artistsMemoizer.get();
1078                         return super.getArtists();
1079                 }
1080
1081                 /**
1082                  * {@inheritDoc}
1083                  */
1084                 @Override
1085                 public Collection<Style> getStyles() {
1086                         stylesMemoizer.get();
1087                         return super.getStyles();
1088                 }
1089
1090                 /**
1091                  * {@inheritDoc}
1092                  */
1093                 @Override
1094                 public List<Artist> getRemixArtists() {
1095                         remixArtistsMemoizer.get();
1096                         return super.getRemixArtists();
1097                 }
1098
1099                 /**
1100                  * {@inheritDoc}
1101                  */
1102                 @Override
1103                 public Collection<TrackDerivative> getDerivatives() {
1104                         derivativesMemoizer.get();
1105                         return super.getDerivatives();
1106                 }
1107
1108                 /**
1109                  * {@inheritDoc}
1110                  */
1111                 @Override
1112                 public Map<Relationship, Collection<Track>> getRelatedTracks() {
1113                         relatedTracksMemoizer.get();
1114                         return super.getRelatedTracks();
1115                 }
1116
1117                 /**
1118                  * {@inheritDoc}
1119                  */
1120                 @Override
1121                 public Collection<Party> getParties() {
1122                         if (!hasValue("parties")) {
1123                                 try {
1124                                         getValue("parties", Collection.class).set(getPartiesByTrackId(getId()));
1125                                 } catch (DatabaseException de1) {
1126                                         throw new RuntimeException("Could not load Parties for Track " + getId() + ".", de1);
1127                                 }
1128                         }
1129                         return super.getParties();
1130                 }
1131
1132         }
1133
1134         /**
1135          * {@link ObjectCreator} implementation that can create {@link Track}
1136          * objects. This specific implementation creates {@link LazyTrack}
1137          * instances.
1138          *
1139          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1140          */
1141         private class TrackCreator implements ObjectCreator<Track> {
1142
1143                 /**
1144                  * {@inheritDoc}
1145                  */
1146                 @Override
1147                 public Track createObject(ResultSet resultSet) throws SQLException {
1148                         return new LazyTrack(resultSet.getString("TRACKS.ID")).setName(resultSet.getString("TRACKS.NAME")).setRemix(resultSet.getString("TRACKS.REMIX"));
1149                 }
1150
1151         }
1152
1153         /**
1154          * {@link ObjectCreator} implementation that can create
1155          * {@link TrackDerivative} objects.
1156          *
1157          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1158          */
1159         private class TrackDerivativeCreator implements ObjectCreator<TrackDerivative> {
1160
1161                 /**
1162                  * {@inheritDoc}
1163                  */
1164                 @Override
1165                 public TrackDerivative createObject(ResultSet resultSet) throws SQLException {
1166                         return new DefaultTrackDerivative(resultSet.getString("TRACK_DERIVATIVES.ID"));
1167                 }
1168
1169         }
1170
1171         /**
1172          * {@link ObjectCreator} implementation that can create {@link Style}
1173          * objects.
1174          *
1175          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1176          */
1177         private class StyleCreator implements ObjectCreator<Style> {
1178
1179                 /**
1180                  * {@inheritDoc}
1181                  */
1182                 @Override
1183                 public Style createObject(ResultSet resultSet) throws SQLException {
1184                         return new DefaultStyle(resultSet.getString("STYLES.ID")).setName(resultSet.getString("STYLES.NAME"));
1185                 }
1186
1187         }
1188
1189         /**
1190          * {@link Party} implementation that loads additional information only on
1191          * demand.
1192          *
1193          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1194          */
1195         private class LazyParty extends DefaultParty {
1196
1197                 /**
1198                  * Creates a new party.
1199                  *
1200                  * @param id
1201                  *            The ID of the party
1202                  */
1203                 public LazyParty(String id) {
1204                         super(id);
1205                 }
1206
1207                 //
1208                 // PARTY METHODS
1209                 //
1210
1211                 /**
1212                  * {@inheritDoc}
1213                  */
1214                 @Override
1215                 public Collection<Track> getReleases() {
1216                         if (!hasValue("releases")) {
1217                                 try {
1218                                         getValue("releases", Collection.class).set(getTracksByParty(getId()));
1219                                 } catch (DatabaseException de1) {
1220                                         throw new RuntimeException("Could not loaded Tracks for Party " + getId() + ".", de1);
1221                                 }
1222                         }
1223                         return super.getReleases();
1224                 }
1225
1226         }
1227
1228         /**
1229          * {@link ObjectCreator} implementation that can create {@link Party}
1230          * objects.
1231          *
1232          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1233          */
1234         private class PartyCreator implements ObjectCreator<Party> {
1235
1236                 /**
1237                  * {@inheritDoc}
1238                  */
1239                 @Override
1240                 public Party createObject(ResultSet resultSet) throws SQLException {
1241                         return new LazyParty(resultSet.getString("PARTIES.ID")).setName(resultSet.getString("PARTIES.NAME"));
1242                 }
1243
1244         }
1245
1246         /**
1247          * {@link User} implementation that retrieves some attributes (such as
1248          * {@link #getOpenIds()}) from the {@link DataManager} on demand.
1249          *
1250          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1251          */
1252         private class LazyUser extends DefaultUser {
1253
1254                 /** Memoizer for a user’s OpenIDs. */
1255                 private final Memoizer<Void> openIdMemoizer = new Memoizer<Void>(new Callable<Void>() {
1256
1257                         @Override
1258                         public Void call() throws Exception {
1259                                 if (!hasValue("openIds")) {
1260                                         getValue("openIds", Collection.class).set(getOpenIdsByUser(getId()));
1261                                 }
1262                                 return null;
1263                         }
1264                 });
1265
1266                 /**
1267                  * Creates a new user.
1268                  *
1269                  * @param id
1270                  *            The ID of the user
1271                  */
1272                 public LazyUser(String id) {
1273                         super(id);
1274                 }
1275
1276                 /**
1277                  * {@inheritDoc}
1278                  */
1279                 @Override
1280                 public Collection<String> getOpenIds() {
1281                         openIdMemoizer.get();
1282                         return super.getOpenIds();
1283                 }
1284
1285         }
1286
1287         /**
1288          * {@link ObjectCreator} implementation that can create {@link User}
1289          * objects. This specific implementation creates {@link LazyUser} instances.
1290          *
1291          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
1292          */
1293         private class UserCreator implements ObjectCreator<User> {
1294
1295                 /**
1296                  * {@inheritDoc}
1297                  */
1298                 @Override
1299                 public User createObject(ResultSet resultSet) throws SQLException {
1300                         return new LazyUser(resultSet.getString("USERS.ID")).setName(resultSet.getString("USERS.NAME")).setPasswordHash(resultSet.getString("USERS.PASSWORD")).setLevel(resultSet.getInt("USERS.LEVEL"));
1301                 }
1302
1303         }
1304
1305 }