This file is indexed.

/usr/lib/python2.7/dist-packages/musicbrainz2/model.py is in python-musicbrainz2 0.7.4-2.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
"""The MusicBrainz domain model.

These classes are part of the MusicBrainz domain model. They may be used
by other modules and don't contain any network or other I/O code. If you
want to request data from the web service, please have a look at
L{musicbrainz2.webservice}.

The most important classes, usually acting as entry points, are
L{Artist}, L{Release}, and L{Track}.

@var VARIOUS_ARTISTS_ID: The ID of the special 'Various Artists' artist.

@var NS_MMD_1: Default namespace prefix for all MusicBrainz metadata.
@var NS_REL_1: Namespace prefix for relations.
@var NS_EXT_1: Namespace prefix for MusicBrainz extensions.

@see: L{musicbrainz2.webservice}

@author: Matthias Friedrich <matt@mafr.de>
"""
try:
	set
except NameError:
	from sets import Set as set

__revision__ = '$Id: model.py 12829 2010-09-15 12:00:11Z luks $'

__all__ = [
	'VARIOUS_ARTISTS_ID', 'NS_MMD_1', 'NS_REL_1', 'NS_EXT_1', 
	'Entity', 'Artist', 'Release', 'Track', 'User', 'ReleaseGroup',
	'Relation', 'Disc', 'ReleaseEvent', 'Label', 'Tag', 'Rating',
	'AbstractAlias', 'ArtistAlias', 'LabelAlias',
]


VARIOUS_ARTISTS_ID = 'http://musicbrainz.org/artist/89ad4ac3-39f7-470e-963a-56509c546377'

# Namespace URI prefixes
#
NS_MMD_1 = 'http://musicbrainz.org/ns/mmd-1.0#'
NS_REL_1 = 'http://musicbrainz.org/ns/rel-1.0#'
NS_EXT_1 = 'http://musicbrainz.org/ns/ext-1.0#'


class Entity(object):
	"""A first-level MusicBrainz class.

	All entities in MusicBrainz have unique IDs (which are absolute URIs)
	as well as any number of L{relations <Relation>} to other entities
	and free text tags. This class is abstract and should not be
	instantiated.

	Relations are differentiated by their I{target type}, that means,
	where they link to. MusicBrainz currently supports four target types
	(artists, releases, tracks, and URLs) each identified using a URI.
	To get all relations with a specific target type, you can use
	L{getRelations} and pass one of the following constants as the
	parameter:

	 - L{Relation.TO_ARTIST}
	 - L{Relation.TO_RELEASE}
	 - L{Relation.TO_TRACK}
	 - L{Relation.TO_URL}

	@see: L{Relation}
	"""

	def __init__(self, id_=None):
		"""Constructor.

		This should only used by derived classes.

		@param id_: a string containing an absolute URI
		"""
		self._id = id_
		self._relations = { }
		self._tags = { }
		self._rating = Rating()

	def getId(self):
		"""Returns a MusicBrainz ID.

		@return: a string containing a URI, or None
		"""
		return self._id

	def setId(self, value):
		"""Sets a MusicBrainz ID.

		@param value: a string containing an absolute URI 
		"""
		self._id = value

	id = property(getId, setId, doc='The MusicBrainz ID.')

	def getRelations(self, targetType=None, relationType=None,
			requiredAttributes=(), direction=None):
		"""Returns a list of relations.

		If C{targetType} is given, only relations of that target
		type are returned. For MusicBrainz, the following target
		types are defined:
		 - L{Relation.TO_ARTIST}
		 - L{Relation.TO_RELEASE}
		 - L{Relation.TO_TRACK}
		 - L{Relation.TO_URL}

		If C{targetType} is L{Relation.TO_ARTIST}, for example,
		this method returns all relations between this Entity and
		artists.

		You may use the C{relationType} parameter to further restrict
		the selection. If it is set, only relations with the given
		relation type are returned. The C{requiredAttributes} sequence
		lists attributes that have to be part of all returned relations.

		If C{direction} is set, only relations with the given reading
		direction are returned. You can use the L{Relation.DIR_FORWARD},
		L{Relation.DIR_BACKWARD}, and L{Relation.DIR_NONE} constants
		for this.

		@param targetType: a string containing an absolute URI, or None
		@param relationType: a string containing an absolute URI, or None
		@param requiredAttributes: a sequence containing absolute URIs
		@param direction: one of L{Relation}'s direction constants
		@return: a list of L{Relation} objects

		@see: L{Entity}
		"""
		allRels = [ ]
		if targetType is not None:
			allRels = self._relations.setdefault(targetType, [ ])
		else:
			for (k, relList) in self._relations.items():
				for rel in relList:
					allRels.append(rel)

		# Filter for direction.
		#
		if direction is not None:
			allRels = [r for r in allRels if r.getDirection() == direction]

		# Filter for relation type.
		#
		if relationType is None:
			return allRels
		else:
			allRels = [r for r in allRels if r.getType() == relationType]

		# Now filer for attribute type.
		#
		tmp = []
		required = set(iter(requiredAttributes))

		for r in allRels:
			attrs = set(iter(r.getAttributes()))
			if required.issubset(attrs):
				tmp.append(r)
		return tmp


	def getRelationTargets(self, targetType=None, relationType=None,
			requiredAttributes=(), direction=None):
		"""Returns a list of relation targets.

		The arguments work exactly like in L{getRelations}, but
		instead of L{Relation} objects, the matching relation
		targets are returned. This can be L{Artist}, L{Release},
		or L{Track} objects, depending on the relations.

		As a special case, URL strings are returned if the target
		is an URL.

		@param targetType: a string containing an absolute URI, or None
		@param relationType: a string containing an absolute URI, or None
		@param requiredAttributes: a sequence containing absolute URIs
		@param direction: one of L{Relation}'s direction constants
		@return: a list of objects, depending on the relation

		@see: L{getRelations}
		"""
		ret = [ ]
		rels =  self.getRelations(targetType, relationType,
			requiredAttributes, direction)

		for r in rels:
			if r.getTargetType() == Relation.TO_URL:
				ret.append(r.getTargetId())
			else:
				ret.append(r.getTarget())

		return ret


	def addRelation(self, relation):
		"""Adds a relation.

		This method adds C{relation} to the list of relations. The
		given relation has to be initialized, at least the target
		type has to be set.

		@param relation: the L{Relation} object to add

		@see: L{Entity}
		"""
		assert relation.getType is not None
		assert relation.getTargetType is not None
		assert relation.getTargetId is not None
		l = self._relations.setdefault(relation.getTargetType(), [ ])
		l.append(relation)


	def getRelationTargetTypes(self):
		"""Returns a list of target types available for this entity.

		Use this to find out to which types of targets this entity
		has relations. If the entity only has relations to tracks and
		artists, for example, then a list containg the strings
		L{Relation.TO_TRACK} and L{Relation.TO_ARTIST} is returned.

		@return: a list of strings containing URIs

		@see: L{getRelations}
		"""
		return self._relations.keys()

	def getTag(self, value):
		"""Return the tag with the given value (aka the tag's name).

		@return: the L{Tag} with the given name or raises a KeyError
		"""
		return self._tags[value]

	def getTags(self):
		"""Return all tags attached to this Entity.

		@return: a list of L{Tag} objects
		"""
		return self._tags.values()

	tags = property(getTags, doc='The tags for this entity.')

	def addTag(self, tag):
		"""Add a new tag.

		This merges an existing tag with the same name.

		@param tag: the L{Tag} object to add

		@see: L{getTags}
		"""
		if self._tags.has_key(tag.value):
			existing = self._tags[tag.value]
			existing.count += tag.count
		else:
			self._tags[tag.value] = tag

	def getRating(self):
		"""Return the rating of this Entity.
		0 = Unrated
		1 - 5 = Rating

		@return: rating
		"""
		return self._rating

	rating = property(getRating, doc='The rating for this entity.')

	def setRating(self, value):
		self._rating = value
		

class Artist(Entity):
	"""Represents an artist.

	Artists in MusicBrainz can have a type. Currently, this type can
	be either Person or Group for which the following URIs are assigned:

	 - C{http://musicbrainz.org/ns/mmd-1.0#Person}
	 - C{http://musicbrainz.org/ns/mmd-1.0#Group}

	Use the L{TYPE_PERSON} and L{TYPE_GROUP} constants for comparison.
	"""
	TYPE_PERSON = NS_MMD_1 + 'Person'
	TYPE_GROUP = NS_MMD_1 + 'Group'

	def __init__(self, id_=None, type_=None, name=None, sortName=None):
		"""Constructor.

		@param id_: a string containing an absolute URI
		@param type_: a string containing an absolute URI
		@param name: a string containing the artist's name
		@param sortName: a string containing the artist's sort name
		"""
		Entity.__init__(self, id_)
		self._type = type_
		self._name = name
		self._sortName = sortName
		self._disambiguation = None
		self._beginDate = None
		self._endDate = None
		self._aliases = [ ]
		self._releases = [ ]
		self._releasesCount = None
		self._releasesOffset = None
		self._releaseGroups = [ ]
		self._releaseGroupsCount = None
		self._releaseGroupsOffset = None

	def getType(self):
		"""Returns the artist's type.

		@return: a string containing an absolute URI, or None 
		"""
		return self._type

	def setType(self, type_):
		"""Sets the artist's type.

		@param type_: a string containing an absolute URI
		"""
		self._type = type_

	type = property(getType, setType, doc="The artist's type.")

	def getName(self):
		"""Returns the artist's name.

		@return: a string containing the artist's name, or None
		"""
		return self._name

	def setName(self, name):
		"""Sets the artist's name.

		@param name: a string containing the artist's name
		"""
		self._name = name

	name = property(getName, setName, doc="The artist's name.")

	def getSortName(self):
		"""Returns the artist's sort name.

		The sort name is the artist's name in a special format which
		is better suited for lexicographic sorting. The MusicBrainz
		style guide specifies this format.

		@see: U{The MusicBrainz Style Guidelines
			<http://musicbrainz.org/style.html>}
		"""
		return self._sortName

	def setSortName(self, sortName):
		"""Sets the artist's sort name.

		@param sortName: a string containing the artist's sort name

		@see: L{getSortName}
		"""
		self._sortName = sortName

	sortName = property(getSortName, setSortName,
		doc="The artist's sort name.")

	def getDisambiguation(self):
		"""Returns the disambiguation attribute.

		This attribute may be used if there is more than one artist
		with the same name. In this case, disambiguation attributes
		are added to the artists' names to keep them apart.

		For example, there are at least three bands named 'Vixen'.
		Each band has a different disambiguation in the MusicBrainz
		database, like 'Hip-hop' or 'all-female rock/glam band'.

		@return: a disambiguation string, or None

		@see: L{getUniqueName}
		"""
		return self._disambiguation

	def setDisambiguation(self, disambiguation):
		"""Sets the disambiguation attribute.

		@param disambiguation: a disambiguation string

		@see: L{getDisambiguation}, L{getUniqueName}
		"""
		self._disambiguation = disambiguation

	disambiguation = property(getDisambiguation, setDisambiguation,
		doc="The disambiguation comment.")

	def getUniqueName(self):
		"""Returns a unique artist name (using disambiguation).

		This method returns the artist name together with the
		disambiguation attribute in parenthesis if it exists.
		Example: 'Vixen (Hip-hop)'.

		@return: a string containing the unique name

		@see: L{getDisambiguation}
		"""
		d = self.getDisambiguation() 
		if d is not None and d.strip() != '':
			return '%s (%s)' % (self.getName(), d)
		else: 
			return self.getName()

	def getBeginDate(self):
		"""Returns the birth/foundation date.

		The definition of the I{begin date} depends on the artist's
		type. For persons, this is the day of birth, for groups it
		is the day the group was founded.

		The returned date has the format 'YYYY', 'YYYY-MM', or 
		'YYYY-MM-DD', depending on how much detail is known.

		@return: a string containing the date, or None

		@see: L{getType}
		"""
		return self._beginDate

	def setBeginDate(self, dateStr):
		"""Sets the begin/foundation date.

		@param dateStr: a date string

		@see: L{getBeginDate}
		"""
		self._beginDate = dateStr

	beginDate = property(getBeginDate, setBeginDate,
		doc="The begin/foundation date.")

	def getEndDate(self):
		"""Returns the death/dissolving date.

		The definition of the I{end date} depends on the artist's
		type. For persons, this is the day of death, for groups it
		is the day the group was dissolved.

		@return: a string containing a date, or None

		@see: L{getBeginDate}
		"""
		return self._endDate

	def setEndDate(self, dateStr):
		"""Sets the death/dissolving date.

		@param dateStr: a string containing a date

		@see: L{setEndDate}, L{getBeginDate}
		"""
		self._endDate = dateStr

	endDate = property(getEndDate, setEndDate,
		doc="The death/dissolving date.")

	def getAliases(self):
		"""Returns the list of aliases for this artist.

		@return: a list of L{ArtistAlias} objects
		"""
		return self._aliases

	aliases = property(getAliases, doc='The list of aliases.')

	def addAlias(self, alias):
		"""Adds an alias for this artist.
		
		@param alias: an L{ArtistAlias} object
		"""
		self._aliases.append(alias)

	def getReleases(self):
		"""Returns a list of releases from this artist.

		This may also include releases where this artist isn't the
		I{main} artist but has just contributed one or more tracks
		(aka VA-Releases).

		@return: a list of L{Release} objects
		"""
		return self._releases

	releases = property(getReleases, doc='The list of releases')

	def addRelease(self, release):
		"""Adds a release to this artist's list of releases.

		@param release: a L{Release} object
		"""
		self._releases.append(release)

	def getReleasesOffset(self):
		"""Returns the offset of the release list.

		This is used if the release list is incomplete (ie. the web
		service only returned part of the release for this artist).
		Note that the offset value is zero-based, which means release
		C{0} is the first release.

		@return: an integer containing the offset, or None

		@see: L{getReleases}, L{getReleasesCount}
		"""
		return self._releasesOffset

	def setReleasesOffset(self, offset):
		"""Sets the offset of the release list.

		@param offset: an integer containing the offset, or None

		@see: L{getReleasesOffset}
		"""
		self._releasesOffset = offset

	releasesOffset = property(getReleasesOffset, setReleasesOffset,
		doc='The offset of the release list.')

	def getReleasesCount(self):
		"""Returns the number of existing releases.
	
		This may or may not match with the number of elements that
		L{getReleases} returns. If the count is higher than
		the list, it indicates that the list is incomplete.

		@return: an integer containing the count, or None

		@see: L{setReleasesCount}, L{getReleasesOffset}
		"""
		return self._releasesCount

	def setReleasesCount(self, value):
		"""Sets the number of existing releases.

		@param value: an integer containing the count, or None

		@see: L{getReleasesCount}, L{setReleasesOffset}
		"""
		self._releasesCount = value

	releasesCount = property(getReleasesCount, setReleasesCount,
		doc='The total number of releases')

	def getReleaseGroups(self):
		"""Returns a list of release groups from this artist.
		
		@return: a list of L{ReleaseGroup} objects
		"""
		return self._releaseGroups
	
	releaseGroups = property(getReleaseGroups, doc='The list of release groups')
	
	def addReleaseGroup(self, releaseGroup):
		"""Adds a release group to this artist's list of release groups.
		
		@param releaseGroup: a L{ReleaseGroup} object
		"""
		self._releaseGroups.append(releaseGroup)

	def getReleaseGroupsOffset(self):
		"""Returns the offset of the release group list.

		This is used if the release group list is incomplete (ie. the
		web service only returned part of the result for this artist).
		Note that the offset value is zero-based, which means release
		group C{0} is the first release group.

		@return: an integer containing the offset, or None

		@see: L{getReleaseGroups}, L{getReleaseGroupsCount}
		"""
		return self._releaseGroupsOffset

	def setReleaseGroupsOffset(self, offset):
		"""Sets the offset of the release group list.

		@param offset: an integer containing the offset, or None

		@see: L{getReleaseGroupsOffset}
		"""
		self._releaseGroupsOffset = offset

	releaseGroupsOffset = property(getReleaseGroupsOffset, setReleaseGroupsOffset,
		doc='The offset of the release group list.')

	def getReleaseGroupsCount(self):
		"""Returns the number of existing release groups.

		This may or may not match with the number of elements that
		L{getReleaseGroups} returns. If the count is higher than
		the list, it indicates that the list is incomplete.

		@return: an integer containing the count, or None

		@see: L{setReleaseGroupsCount}, L{getReleaseGroupsOffset}
		"""
		return self._releaseGroupsCount

	def setReleaseGroupsCount(self, value):
		"""Sets the number of existing release groups.

		@param value: an integer containing the count, or None

		@see: L{getReleaseGroupsCount}, L{setReleaseGroupsOffset}
		"""
		self._releaseGroupsCount = value

	releasesCount = property(getReleaseGroupsCount, setReleaseGroupsCount,
		doc='The total number of release groups')


class Rating(object):
	"""The representation of a MusicBrain rating.

	The rating can have the following values:

	0 = Unrated
	[1..5] = Rating
	"""
	def __init__(self, value=None, count=None):
		"""Constructor.

		@param value: a string containing the tag's value
		@param count: the number of users who added this tag
		"""
		self._value = value
		self._count = count

	def getValue(self):
		"""Returns a string with the tag's value.

		@return: an integer containing the rating's value, or None
		"""
		return self._value

	def setValue(self, value):
		""" Set the value of this rating.

		0 or None = Clear your rating
		1 - 5 = Rating

		@param value: the rating to apply

		@raise ValueError: if value is not a double or not in the
		range 0 - 5 or None.
		"""
		if value == None:
		  value = 0
		try:
		  value = float(value)
		except ValueError, e:
		  raise ValueError("Value for rating needs to be an" \
		      "float.")
		if value < 0.0 or value > 5.0:
		  raise ValueError("Value needs to be in the range [0..5]")
		self._value = value

	value = property(getValue, setValue, doc='The value of the rating.')

	def getCount(self):
		"""Returns an integer containing the rating's frequency count.

		@return: an integer containing the rating's frequency count,
		or None
		"""
		return self._count
	
	def setCount(self, count):
		"""Sets the frequency count of this rating.
		
		@param count: an integer containing the tag's frequency count
		"""
		self._count = count
		
	count = property(getCount, setCount, doc="This tag's frequency count.")

	def __str__(self):
		return str(self._value)

	def __unicode__(self):
		return unicode(self._value)


class Tag(object):
	"""The representation of a MusicBrainz folksonomy tag.

	The tag's value is the text that's displayed in the tag cloud.
	The count attribute keeps track of how many users added the tag
	to its owning entity.
	"""
	def __init__(self, value=None, count=None):
		"""Constructor.

		@param value: a string containing the tag's value
		@param count: the number of users who added this tag
		"""
		self._value = value
		self._count = count

	def getValue(self):
		"""Returns a string with the tag's value.

		@return: a string containing the tags's value, or None
		"""
		return self._value
	
	def setValue(self, value):
		"""Sets the value of this tag.
		
		@param value: A string containing the value of the tag
		"""
		self._value = value
		
	value = property(getValue, setValue, doc='The value of the text.')

	def getCount(self):
		"""Returns an integer containing the tag's frequency count.

		@return: an integer containing the tags's frequency count, or None
		"""
		return self._count
	
	def setCount(self, count):
		"""Sets the frequency count of this tag.
		
		@param count: an integer containing the tag's frequency count
		"""
		self._count = count
		
	count = property(getCount, setCount, doc="This tag's frequency count.")

	def __str__(self):
		return str(self._value)

	def __unicode__(self):
		return unicode(self._value)


class Label(Entity):
	"""Represents a record label.
	
	A label within MusicBrainz is an L{Entity}. It contains information
	about the label like when it was established, its name, label code and
	other relationships. All release events may be assigned a label.
	"""
	TYPE_UNKNOWN = NS_MMD_1 + 'Unknown'
	
	TYPE_DISTRIBUTOR = NS_MMD_1 + 'Distributor'
	TYPE_HOLDING = NS_MMD_1 + 'Holding'
	TYPE_PRODUCTION = NS_MMD_1 + 'Production'
	
	TYPE_ORIGINAL = NS_MMD_1 + 'OriginalProduction'
	TYPE_BOOTLEG = NS_MMD_1 + 'BootlegProduction'
	TYPE_REISSUE = NS_MMD_1 + 'ReissueProduction'
	
	def __init__(self, id_=None):
		"""Constructor.

		@param id_: a string containing an absolute URI
		"""
		Entity.__init__(self, id_)
		self._type = None
		self._name = None
		self._sortName = None
		self._disambiguation = None
		self._countryId = None
		self._code = None
		self._beginDate = None
		self._endDate = None
		self._aliases = [ ]
	
	def getType(self):
		"""Returns the type of this label.

		@return: a string containing an absolute URI
		"""
		return self._type
	
	def setType(self, type_):
		"""Sets the type of this label.
		
		@param type_: A string containing the absolute URI of the type of label.
		"""
		self._type = type_
	
	type = property(getType, setType, doc='The type of label')
	
	def getName(self):
		"""Returns a string with the name of the label.

		@return: a string containing the label's name, or None
		"""
		return self._name
	
	def setName(self, name):
		"""Sets the name of this label.
		
		@param name: A string containing the name of the label
		"""
		self._name = name
		
	name = property(getName, setName, doc='The name of the label.')
	
	def getSortName(self):
		"""Returns the label's sort name.

		The sort name is the label's name in a special format which
		is better suited for lexicographic sorting. The MusicBrainz
		style guide specifies this format.

		@see: U{The MusicBrainz Style Guidelines
			<http://musicbrainz.org/style.html>}
		"""
		return self._sortName

	def setSortName(self, sortName):
		"""Sets the label's sort name.

		@param sortName: a string containing the label's sort name

		@see: L{getSortName}
		"""
		self._sortName = sortName

	sortName = property(getSortName, setSortName,
		doc="The label's sort name.")

	def getDisambiguation(self):
		"""Returns the disambiguation attribute.

		This attribute may be used if there is more than one label
		with the same name. In this case, disambiguation attributes
		are added to the labels' names to keep them apart.

		@return: a disambiguation string, or None

		@see: L{getUniqueName}
		"""
		return self._disambiguation

	def setDisambiguation(self, disambiguation):
		"""Sets the disambiguation attribute.

		@param disambiguation: a disambiguation string

		@see: L{getDisambiguation}, L{getUniqueName}
		"""
		self._disambiguation = disambiguation

	disambiguation = property(getDisambiguation, setDisambiguation,
		doc="The disambiguation comment.")

	def getUniqueName(self):
		"""Returns a unique label name (using disambiguation).

		This method returns the label's name together with the
		disambiguation attribute in parenthesis if it exists.

		@return: a string containing the unique name

		@see: L{getDisambiguation}
		"""
		d = self.getDisambiguation() 
		if d is not None and d.strip() != '':
			return '%s (%s)' % (self.getName(), d)
		else: 
			return self.getName()

	def getBeginDate(self):
		"""Returns the date this label was established.
		
		@return: A string contained the start date, or None
		"""
		return self._beginDate
	
	def setBeginDate(self, date):
		"""Set the date this label was established.
		
		@param date: A string in the format of YYYY-MM-DD
		"""
		self._beginDate = date
	
	beginDate = property(getBeginDate, setBeginDate,
		doc='The date this label was established.')

	def getEndDate(self):
		"""Returns the date this label closed.

		The returned date has the format 'YYYY', 'YYYY-MM', or 
		'YYYY-MM-DD', depending on how much detail is known.
		
		@return: A string containing the date, or None
		"""
		return self._endDate
	
	def setEndDate(self, date):
		"""Set the date this label closed.

		The date may have the format 'YYYY', 'YYYY-MM', or 
		'YYYY-MM-DD', depending on how much detail is known.
		
		@param date: A string containing the date, or None
		"""
		self._endDate = date
	
	endDate = property(getEndDate, setEndDate,
		doc='The date this label closed.')
		
	def getCountry(self):
		"""Returns the country the label is located.

		@return: a string containing an ISO-3166 country code, or None

		@see: L{musicbrainz2.utils.getCountryName}
		"""
		return self._countryId

	def setCountry(self, country):
		"""Sets the country the label is located.

		@param country: a string containing an ISO-3166 country code
		"""
		self._countryId = country

	country = property(getCountry, setCountry,
		doc='The country the label is located.')

	def getCode(self):
		"""Returns the label code.

		Label codes have been introduced by the IFPI (International
		Federation of Phonogram and Videogram Industries) to uniquely
		identify record labels. The label code consists of 'LC-' and 4
		figures (currently being extended to 5 figures).

		@return: a string containing the label code, or None
		"""
		return self._code

	def setCode(self, code):
		"""Sets the label code.

		@param code: a string containing the label code
		"""
		self._code = code

	code = property(getCode, setCode,
		doc='The label code.')

	def getAliases(self):
		"""Returns the list of aliases for this label.

		@return: a list of L{LabelAlias} objects
		"""
		return self._aliases

	aliases = property(getAliases, doc='The list of aliases.')

	def addAlias(self, alias):
		"""Adds an alias for this label.
		
		@param alias: a L{LabelAlias} object
		"""
		self._aliases.append(alias)


class Release(Entity):
	"""Represents a Release.

	A release within MusicBrainz is an L{Entity} which contains L{Track}
	objects.  Releases may be of more than one type: There can be albums,
	singles, compilations, live recordings, official releases, bootlegs
	etc.

	@note: The current MusicBrainz server implementation supports only a
	limited set of types.
	"""
	TYPE_NONE = NS_MMD_1 + 'None'
	TYPE_NON_ALBUM_TRACKS = NS_MMD_1 + "NonAlbum Track"

	TYPE_ALBUM = NS_MMD_1 + 'Album'
	TYPE_SINGLE = NS_MMD_1 + 'Single'
	TYPE_EP = NS_MMD_1 + 'EP'
	TYPE_COMPILATION = NS_MMD_1 + 'Compilation'
	TYPE_SOUNDTRACK = NS_MMD_1 + 'Soundtrack'
	TYPE_SPOKENWORD = NS_MMD_1 + 'Spokenword'
	TYPE_INTERVIEW = NS_MMD_1 + 'Interview'
	TYPE_AUDIOBOOK = NS_MMD_1 + 'Audiobook'
	TYPE_LIVE = NS_MMD_1 + 'Live'
	TYPE_REMIX = NS_MMD_1 + 'Remix'
	TYPE_OTHER = NS_MMD_1 + 'Other'

	TYPE_OFFICIAL = NS_MMD_1 + 'Official'
	TYPE_PROMOTION = NS_MMD_1 + 'Promotion'
	TYPE_BOOTLEG = NS_MMD_1 + 'Bootleg'
	TYPE_PSEUDO_RELEASE = NS_MMD_1 + 'Pseudo-Release'

	def __init__(self, id_=None, title=None):
		"""Constructor.

		@param id_: a string containing an absolute URI
		@param title: a string containing the title
		"""
		Entity.__init__(self, id_)
		self._types = [ ]
		self._title = title
		self._textLanguage = None
		self._textScript = None
		self._asin = None
		self._artist = None
		self._releaseEvents = [ ]
		#self._releaseEventsCount = None
		self._releaseGroup = None
		self._discs = [ ]
		#self._discIdsCount = None
		self._tracks = [ ]
		self._tracksOffset = None
		self._tracksCount = None


	def getTypes(self):
		"""Returns the types of this release.

		To test for release types, you can use the constants
		L{TYPE_ALBUM}, L{TYPE_SINGLE}, etc.

		@return: a list of strings containing absolute URIs

		@see: L{musicbrainz2.utils.getReleaseTypeName}
		"""
		return self._types

	types = property(getTypes, doc='The list of types for this release.')

	def addType(self, type_):
		"""Add a type to the list of types.

		@param type_: a string containing absolute URIs

		@see: L{getTypes}
		"""
		self._types.append(type_)

	def getTitle(self):
		"""Returns the release's title.

		@return: a string containing the release's title
		"""
		return self._title

	def setTitle(self, title):
		"""Sets the release's title.

		@param title: a string containing the release's title, or None
		"""
		self._title = title

	title = property(getTitle, setTitle, doc='The title of this release.')

	def getTextLanguage(self):
		"""Returns the language used in release and track titles.

		To represent the language, the ISO-639-2/T standard is used,
		which provides three-letter terminological language codes like
		'ENG', 'DEU', 'JPN', 'KOR', 'ZHO' or 'YID'.

		Note that this refers to release and track I{titles}, not
		lyrics.

		@return: a string containing the language code, or None

		@see: L{musicbrainz2.utils.getLanguageName}
		"""
		return self._textLanguage

	def setTextLanguage(self, language):
		"""Sets the language used in releaes and track titles.

		@param language: a string containing a language code

		@see: L{getTextLanguage}
		"""
		self._textLanguage = language

	textLanguage = property(getTextLanguage, setTextLanguage,
		doc='The language used in release and track titles.')

	def getTextScript(self):
		"""Returns the script used in release and track titles.

		To represent the script, ISO-15924 script codes are used.
		Valid codes are, among others: 'Latn', 'Cyrl', 'Hans', 'Hebr'

		Note that this refers to release and track I{titles}, not
		lyrics.

		@return: a string containing the script code, or None

		@see: L{musicbrainz2.utils.getScriptName}
		"""
		return self._textScript

	def setTextScript(self, script):
		"""Sets the script used in releaes and track titles.

		@param script: a string containing a script code

		@see: L{getTextScript}
		"""
		self._textScript = script

	textScript = property(getTextScript, setTextScript,
		doc='The script used in release and track titles.')

	def getAsin(self):
		"""Returns the amazon shop identifier (ASIN).

		The ASIN is a 10-letter code (except for books) assigned
		by Amazon, which looks like 'B000002IT2' or 'B00006I4YD'.

		@return: a string containing the ASIN, or None
		"""
		return self._asin

	def setAsin(self, asin):
		"""Sets the amazon shop identifier (ASIN).

		@param asin: a string containing the ASIN

		@see: L{getAsin}
		"""
		self._asin = asin

	asin = property(getAsin, setAsin, doc='The amazon shop identifier.')

	def getArtist(self):
		"""Returns the main artist of this release.

		@return: an L{Artist} object, or None
		"""
		return self._artist

	def setArtist(self, artist):
		"""Sets this release's main artist.

		@param artist: an L{Artist} object
		"""
		self._artist = artist

	artist = property(getArtist, setArtist,
		doc='The main artist of this release.')

	def getReleaseGroup(self):
		"""Returns the release group to which this release belongs.
		
		@return: a L{ReleaseGroup} object, or None.
		"""
		return self._releaseGroup

	def setReleaseGroup(self, releaseGroup):
		"""Sets the release's release group.
		
		@param releaseGroup: a L{ReleaseGroup} object, or None.
		"""
		self._releaseGroup = releaseGroup

	releaseGroup = property(getReleaseGroup, setReleaseGroup,
		doc='The release group this release belongs to.')

	def isSingleArtistRelease(self):
		"""Checks if this is a single artist's release.

		Returns C{True} if the release's main artist (L{getArtist}) is
		also the main artist for all of the tracks. This is checked by
		comparing the artist IDs.

		Note that the release's artist has to be set (see L{setArtist})
		for this. The track artists may be unset.

		@return: True, if this is a single artist's release
		"""
		releaseArtist = self.getArtist()
		assert releaseArtist is not None, 'Release Artist may not be None!'
		for track in self.getTracks():
			if track.getArtist() is None:
				continue
			if track.getArtist().getId() != releaseArtist.getId():
				return False

		return True

	def getTracks(self):
		"""Returns the tracks this release contains.

		@return: a list containing L{Track} objects

		@see: L{getTracksOffset}, L{getTracksCount}
		"""
		return self._tracks

	tracks = property(getTracks, doc='The list of tracks.')

	def addTrack(self, track):
		"""Adds a track to this release.

		This appends a track at the end of this release's track list.

		@param track: a L{Track} object
		"""
		self._tracks.append(track)

	def getTracksOffset(self):
		"""Returns the offset of the track list.

		This is used if the track list is incomplete (ie. the web
		service only returned part of the tracks on this release).
		Note that the offset value is zero-based, which means track
		C{0} is the first track.

		@return: an integer containing the offset, or None

		@see: L{getTracks}, L{getTracksCount}
		"""
		return self._tracksOffset

	def setTracksOffset(self, offset):
		"""Sets the offset of the track list.

		@param offset: an integer containing the offset, or None

		@see: L{getTracksOffset}, L{setTracksCount}
		"""
		self._tracksOffset = offset

	tracksOffset = property(getTracksOffset, setTracksOffset,
		doc='The offset of the track list.')

	def getTracksCount(self):
		"""Returns the number of tracks on this release.
	
		This may or may not match with the number of elements that
		L{getTracks} returns. If the count is higher than
		the list, it indicates that the list is incomplete.

		@return: an integer containing the count, or None

		@see: L{setTracksCount}, L{getTracks}, L{getTracksOffset}
		"""
		return self._tracksCount

	def setTracksCount(self, value):
		"""Sets the number of tracks on this release.

		@param value: an integer containing the count, or None

		@see: L{getTracksCount}, L{setTracksOffset}
		"""
		self._tracksCount = value

	tracksCount = property(getTracksCount, setTracksCount,
		doc='The total number of releases')


	def getReleaseEvents(self):
		"""Returns the list of release events.

		A L{Release} may contain a list of so-called release events,
		each represented using a L{ReleaseEvent} object. Release
		evens specify where and when this release was, well, released.

		@return: a list of L{ReleaseEvent} objects

		@see: L{getReleaseEventsAsDict}
		"""
		return self._releaseEvents

	releaseEvents = property(getReleaseEvents,
		doc='The list of release events.')

	def addReleaseEvent(self, event):
		"""Adds a release event to this release.

		@param event: a L{ReleaseEvent} object

		@see: L{getReleaseEvents}
		"""
		self._releaseEvents.append(event)

	def getReleaseEventsAsDict(self):
		"""Returns the release events represented as a dict.

		Keys are ISO-3166 country codes like 'DE', 'UK', 'FR' etc.
		Values are dates in 'YYYY', 'YYYY-MM' or 'YYYY-MM-DD' format.

		@return: a dict containing (countryCode, date) entries

		@see: L{getReleaseEvents}, L{musicbrainz2.utils.getCountryName}
		"""
		d = { }
		for event in self.getReleaseEvents():
			d[event.getCountry()] = event.getDate()
		return d

	def getEarliestReleaseDate(self):
		"""Returns the earliest release date.

		This favours complete dates. For example, '2006-09' is
		returned if there is '2000', too. If there is no release
		event associated with this release, None is returned.

		@return: a string containing the date, or None 

		@see: L{getReleaseEvents}, L{getReleaseEventsAsDict}
		"""
		event = self.getEarliestReleaseEvent()

		if event is None:
			return None
		else:
			return event.getDate()

	def getEarliestReleaseEvent(self):
		"""Returns the earliest release event.

		This works like L{getEarliestReleaseDate}, but instead of
		just the date, this returns a L{ReleaseEvent} object.

		@return: a L{ReleaseEvent} object, or None 

		@see: L{getReleaseEvents}, L{getEarliestReleaseDate}
		"""
		dates = [ ]
		for event in self.getReleaseEvents():
			date = event.getDate()
			if len(date) == 10:    # 'YYYY-MM-DD'
				dates.append( (date, event) )
			elif len(date) == 7:   # 'YYYY-MM'
				dates.append( (date + '-99', event) )
			else:
				dates.append( (date + '-99-99', event) )

		dates.sort(lambda x, y: cmp(x[0], y[0]))

		if len(dates) > 0:
			return dates[0][1]
		else:
			return None


	#def getReleaseEventsCount(self):
	#	"""Returns the number of release events.
	#
	#	This may or may not match with the number of elements that
	#	getReleaseEvents() returns. If the count is higher than
	#	the list, it indicates that the list is incomplete.
	#	"""
	#	return self._releaseEventsCount

	#def setReleaseEventsCount(self, value):
	#	self._releaseEventsCount = value

	def getDiscs(self):
		"""Returns the discs associated with this release.

		Discs are currently containers for MusicBrainz DiscIDs.
		Note that under rare circumstances (identical TOCs), a
		DiscID could be associated with more than one release.

		@return: a list of L{Disc} objects
		"""
		return self._discs

	discs = property(getDiscs, doc='The list of associated discs.')

	def addDisc(self, disc):
		"""Adds a disc to this release.

		@param disc: a L{Disc} object
		"""
		self._discs.append(disc)

	#def getDiscIdsCount(self):
	#	return self._discIdsCount

	#def setDiscIdsCount(self, value):
	#	self._discIdsCount = value


class ReleaseGroup(Entity):
	"""Represents a ReleaseGroup.

	A ReleaseGroup in MusicBrainz is an L{Entity} which groups several different
	versions of L{Release} objects (e.g., different editions of the same album).

	@see: L{Release}
	@see: L{Entity}
	"""

	def __init__(self, id_=None, title=None):
		"""Constructor.

		@param id_: a string containing an absolute URI
		@param title: a string containing the title
		"""
		Entity.__init__(self, id_)
		self._title = title
		self._id = id_
		self._type = None
		self._releases = [ ]
		self._artist = None
		self._releasesOffset = 0
		self._releasesCount = 0

	def getType(self):
		"""Returns the type of this release group.

		To test for release types, you can use the constants
		L{Release.TYPE_ALBUM}, L{Release.TYPE_SINGLE}, etc.

		@return: a string containing an absolute URI, or None.

		@see: L{musicbrainz2.utils.getReleaseTypeName}
		"""
		return self._type

	def setType(self, type_):
		"""Sets the type of this release group.

		Use a constant from the L{Release} class, such as
		L{Release.TYPE_ALBUM} or L{Release.TYPE_SINGLE} to
		set the value.

		@param type_: a string containing an absolute URI, or None.
		
		@see: L{musicbrainz2.utils.getReleaseTypeName}
		"""
		self._type = type_

	type = property(getType, setType,
		doc = 'The type of this release group.')

	def getReleases(self):
		"""Gets the releases in this release group.

		@return: a list of L{Release} objects
		@see: L{Release}
		"""
		return self._releases

	releases = property(getReleases,
		doc = 'The list of releases in this release group.')

	def addRelease(self, release):
		"""Adds a L{Release} to this release group.

		@param release: a L{Release} object
		"""
		self._releases.append(release)

	def getReleasesOffset(self):
		"""Returns the offset of the release list.

		This is used if the release list is incomplete (i.e., the web
		service only returned a portion of the releases in this release
		group).

		@return: an integer containing the offset, or None.
		@see: L{getReleases}, L{getReleasesCount}
		"""
		return self._releasesOffset

	def setReleasesOffset(self, offset):
		"""Sets the offset of the release list.

		@param offset: an integer containing the offset, or None.
		@see: L{getReleases}, L{getReleasesOffset}
		"""
		self._releasesOffset = offset

	releasesOffset = property(getReleasesOffset, setReleasesOffset,
		doc='The offset of the release list.')

	def getReleasesCount(self):
		"""Returns the number of releases in this release group.

		This may or may not match the number of elements returned by
		L{getReleases}.  If the count is higher than the length of that
		list, then the list is incomplete.

		@return: an integer containing the count, or None
		@see: L{getReleases}, L{setReleasesCount}, L{getReleasesOffset}
		"""
		return self._releasesCount

	def setReleasesCount(self, value):
		"""Sets the number of releases in this release group.

		@param value: an integer containing the count, or None.
		@see: L{getReleases}, L{getReleasesCount}, L{getReleasesOffset}
		"""
		self._releasesCount = value

	releasesCount = property(getReleasesCount, setReleasesCount,
		doc = 'The total number of releases')

	def getTitle(self):
		"""Returns this release group's title.

		@return: a string containing the release group's title
		"""
		return self._title

	def setTitle(self, title):
		"""Sets the release group's title.

		@param title: a string containing the release group's title.
		"""
		self._title = title

	title = property(getTitle, setTitle,
		doc = 'The title of this release group.')

	def getArtist(self):
		"""Returns the main artist of this release group.

		@return: an L{Artist} object, or None
		"""
		return self._artist

	def setArtist(self, artist):
		"""Sets the release group's main artist.

		@param artist: an L{Artist} object
		"""
		self._artist = artist

	artist = property(getArtist, setArtist,
		doc = 'The main artist of this release group')


class Track(Entity):
	"""Represents a track.

	This class represents a track which may appear on one or more releases.
	A track may be associated with exactly one artist (the I{main} artist).

	Using L{getReleases}, you can find out on which releases this track
	appears. To get the track number, too, use the
	L{Release.getTracksOffset} method.

	@note: Currently, the MusicBrainz server doesn't support tracks to
	       be on more than one release.

	@see: L{Release}, L{Artist}
	"""
	def __init__(self, id_=None, title=None):
		"""Constructor.

		@param id_: a string containing an absolute URI
		@param title: a string containing the title
		"""
		Entity.__init__(self, id_)
		self._title = title
		self._artist = None
		self._duration = None
		self._puids = [ ]
		self._releases = [ ]
		self._isrcs = [ ]

	def getTitle(self):
		"""Returns the track's title.

		The style and format of this attribute is specified by the
		style guide.

		@return: a string containing the title, or None

		@see: U{The MusicBrainz Style Guidelines
			<http://musicbrainz.org/style.html>}
		"""
		return self._title

	def setTitle(self, title):
		"""Sets the track's title.

		@param title: a string containing the title

		@see: L{getTitle}
		"""
		self._title = title

	title = property(getTitle, setTitle, doc="The track's title.")

	def getArtist(self):
		"""Returns the main artist of this track.

		@return: an L{Artist} object, or None
		"""
		return self._artist

	def setArtist(self, artist):
		"""Sets this track's main artist.

		@param artist: an L{Artist} object
		"""
		self._artist = artist

	artist = property(getArtist, setArtist, doc="The track's main artist.")

	def getDuration(self):
		"""Returns the duration of this track in milliseconds.

		@return: an int containing the duration in milliseconds, or None
		"""
		return self._duration

	def setDuration(self, duration):
		"""Sets the duration of this track in milliseconds.

		@param duration: an int containing the duration in milliseconds
		"""
		self._duration = duration

	duration = property(getDuration, setDuration,
		doc='The duration in milliseconds.')

	def getDurationSplit(self):
		"""Returns the duration as a (minutes, seconds) tuple.

		If no duration is set, (0, 0) is returned. Seconds are
		rounded towards the ceiling if at least 500 milliseconds
		are left.

		@return: a (minutes, seconds) tuple, both entries being ints
		"""
		duration = self.getDuration()
		if duration is None:
			return (0, 0)
		else:
			seconds = int( round(duration / 1000.0) )
			return (seconds / 60, seconds % 60)

	def getPuids(self):
		"""Returns the PUIDs associated with this track.

		Please note that a PUID may be associated with more than one
		track.

		@return: a list of strings, each containing one PUID
		"""
		return self._puids

	puids = property(getPuids, doc='The list of associated PUIDs.')

	def addPuid(self, puid):
		"""Add a PUID to this track.

		@param puid: a string containing a PUID
		"""
		self._puids.append(puid)
	
	def getISRCs(self):
		"""Returns the ISRCs associated with this track.

		@return: a list of strings, each containing one ISRC
		"""
		return self._isrcs

	isrcs = property(getISRCs, doc='The list of associated ISRCs')

	def addISRC(self, isrc):
		"""Add a ISRC to this track.

		@param isrc: a string containing an ISRC
		"""
		self._isrcs.append(isrc)

	def getReleases(self):
		"""Returns the list of releases this track appears on.

		@return: a list of L{Release} objects
		"""
		return self._releases

	releases = property(getReleases,
		doc='The releases on which this track appears.')

	def addRelease(self, release):
		"""Add a release on which this track appears.

		@param release: a L{Release} object
		"""
		self._releases.append(release)


class Relation(object):
	"""Represents a relation between two Entities.

	There may be an arbitrary number of relations between all first
	class objects in MusicBrainz. The Relation itself has multiple
	attributes, which may or may not be used for a given relation
	type.

	Note that a L{Relation} object only contains the target but not
	the source end of the relation.

	@todo: Add some examples.

	@cvar TO_ARTIST: Identifies relations linking to an artist.
	@cvar TO_RELEASE: Identifies relations linking to a release.
	@cvar TO_TRACK: Identifies relations linking to a track.
	@cvar TO_URL: Identifies relations linking to an URL.

	@cvar DIR_NONE: Relation reading direction doesn't matter.
	@cvar DIR_FORWARD: Relation reading direction is from source to target.
	@cvar DIR_BACKWARD: Relation reading direction is from target to source.
	@cvar DIR_BOTH: Relation reading direction doesn't matter (no longer used!).
	"""
	# Relation target types
	#
	TO_ARTIST = NS_REL_1 + 'Artist'
	TO_RELEASE = NS_REL_1 + 'Release'
	TO_TRACK = NS_REL_1 + 'Track'
	TO_URL = NS_REL_1 + 'Url'

	# Relation reading directions
	#
	DIR_BOTH = 'both'
	DIR_FORWARD = 'forward'
	DIR_BACKWARD = 'backward'
	DIR_NONE = 'none'

	def __init__(self, relationType=None, targetType=None, targetId=None,
			direction=DIR_NONE, attributes=None,
			beginDate=None, endDate=None, target=None):
		"""Constructor.

		@param relationType: a string containing an absolute URI
		@param targetType: a string containing an absolute URI
		@param targetId: a string containing an absolute URI
		@param direction: one of C{Relation.DIR_FORWARD},
		C{Relation.DIR_BACKWARD}, or C{Relation.DIR_NONE}
		@param attributes: a list of strings containing absolute URIs
		@param beginDate: a string containing a date
		@param endDate: a string containing a date
		@param target: an instance of a subclass of L{Entity}
		"""
		self._relationType = relationType
		self._targetType = targetType
		self._targetId = targetId
		self._direction = direction
		self._beginDate = beginDate
		self._endDate = endDate
		self._target = target
		self._attributes = attributes
		if self._attributes is None:
			self._attributes = [ ]

	def getType(self):
		"""Returns this relation's type.

		@return: a string containing an absolute URI, or None 
		"""
		return self._relationType

	def setType(self, type_):
		"""Sets this relation's type.

		@param type_: a string containing an absolute URI
		"""
		self._relationType = type_

	type = property(getType, setType, doc="The relation's type.")

	def getTargetId(self):
		"""Returns the target's ID.

		This is the ID the relation points to. It is an absolute
		URI, and in case of an URL relation, it is a URL.

		@return: a string containing an absolute URI
		"""
		return self._targetId

	def setTargetId(self, targetId):
		"""Sets the target's ID.

		@param targetId: a string containing an absolute URI

		@see: L{getTargetId}
		"""
		self._targetId = targetId

	targetId = property(getTargetId, setTargetId, doc="The target's ID.")

	def getTargetType(self):
		"""Returns the target's type.

		For MusicBrainz data, the following target types are defined:
		 - artists: L{Relation.TO_ARTIST}
		 - releases: L{Relation.TO_RELEASE}
		 - tracks: L{Relation.TO_TRACK}
		 - urls: L{Relation.TO_URL}

		@return: a string containing an absolute URI
		"""
		return self._targetType

	def setTargetType(self, targetType):
		"""Sets the target's type.

		@param targetType: a string containing an absolute URI

		@see: L{getTargetType}
		"""
		self._targetType = targetType

	targetId = property(getTargetId, setTargetId,
		doc="The type of target this relation points to.")

	def getAttributes(self):
		"""Returns a list of attributes describing this relation.

		The attributes permitted depend on the relation type.

		@return: a list of strings containing absolute URIs
		"""
		return self._attributes

	attributes = property(getAttributes,
		doc='The list of attributes describing this relation.')

	def addAttribute(self, attribute):
		"""Adds an attribute to the list.

		@param attribute: a string containing an absolute URI
		"""
		self._attributes.append(attribute)

	def getBeginDate(self):
		"""Returns the begin date.

		The definition depends on the relation's type. It may for
		example be the day of a marriage or the year an artist
		joined a band. For other relation types this may be
		undefined.

		@return: a string containing a date
		"""
		return self._beginDate

	def setBeginDate(self, dateStr):
		"""Sets the begin date.

		@param dateStr: a string containing a date

		@see: L{getBeginDate}
		"""
		self._beginDate = dateStr

	beginDate = property(getBeginDate, setBeginDate, doc="The begin date.")

	def getEndDate(self):
		"""Returns the end date.

		As with the begin date, the definition depends on the
		relation's type. Depending on the relation type, this may
		or may not be defined.

		@return: a string containing a date

		@see: L{getBeginDate}
		"""
		return self._endDate

	def setEndDate(self, dateStr):
		"""Sets the end date.

		@param dateStr: a string containing a date

		@see: L{getBeginDate}
		"""
		self._endDate = dateStr

	endDate = property(getEndDate, setEndDate, doc="The end date.")

	def getDirection(self):
		"""Returns the reading direction.

		The direction may be one of L{Relation.DIR_FORWARD},
		L{Relation.DIR_BACKWARD}, or L{Relation.DIR_NONE},
		depending on how the relation should be read. For example,
		if direction is L{Relation.DIR_FORWARD} for a cover relation,
		it is read as "X is a cover of Y". For some relations there is
		no reading direction (like marriages) and the web service doesn't
		send a direction. In these cases, the direction is set to
		L{Relation.DIR_NONE}.

		@return: L{Relation.DIR_FORWARD}, L{Relation.DIR_BACKWARD},
		or L{Relation.DIR_NONE}
		"""
		return self._direction

	def setDirection(self, direction):
		"""Sets the reading direction.

		@param direction: L{Relation.DIR_FORWARD},
		L{Relation.DIR_BACKWARD}, or L{Relation.DIR_NONE}

		@see: L{getDirection}
		"""
		self._direction = direction

	direction = property(getDirection, setDirection,
		doc="The reading direction.")

	def getTarget(self):
		"""Returns this relation's target object.

		Note that URL relations never have a target object. Use the
		L{getTargetId} method to get the URL.

		@return: a subclass of L{Entity}, or None
		"""
		return self._target

	def setTarget(self, target):
		"""Sets this relation's target object.

		Note that URL relations never have a target object, they
		are set using L{setTargetId}.

		@param target: a subclass of L{Entity}
		"""
		self._target = target

	target = property(getTarget, setTarget,
		doc="The relation's target object.")


class ReleaseEvent(object):
	"""A release event, indicating where and when a release took place.

	All country codes used must be valid ISO-3166 country codes (i.e. 'DE',
	'UK' or 'FR'). The dates are strings and must have the format 'YYYY',
	'YYYY-MM' or 'YYYY-MM-DD'.

	The format of the release medium is a URI that can be compared to the
	constants on this class (L{FORMAT_CD}, L{FORMAT_DVD} and others).
	"""
	FORMAT_CD = NS_MMD_1 + 'CD'
	FORMAT_DVD = NS_MMD_1 + 'DVD'
	FORMAT_SACD = NS_MMD_1 + 'SACD'
	FORMAT_DUALDISC = NS_MMD_1 + 'DualDisc'
	FORMAT_LASERDISC = NS_MMD_1 + 'LaserDisc'
	FORMAT_MINIDISC = NS_MMD_1 + 'MiniDisc'
	FORMAT_VINYL = NS_MMD_1 + 'Vinyl'
	FORMAT_CASSETTE = NS_MMD_1 + 'Cassette'
	FORMAT_CARTRIDGE = NS_MMD_1 + 'Cartridge'
	FORMAT_REEL_TO_REEL = NS_MMD_1 + 'ReelToReel'
	FORMAT_DAT = NS_MMD_1 + 'DAT'
	FORMAT_DIGITAL = NS_MMD_1 + 'Digital'
	FORMAT_WAX_CYLINDER = NS_MMD_1 + 'WaxCylinder'
	FORMAT_PIANO_ROLL = NS_MMD_1 + 'PianoRoll'
	FORMAT_OTHER = NS_MMD_1 + 'Other'

	def __init__(self, country=None, dateStr=None):
		"""Constructor.

		@param country: a string containing an ISO-3166 country code
		@param dateStr: a string containing a date string
		"""
		self._countryId = country
		self._dateStr = dateStr
		self._catalogNumber = None
		self._barcode = None
		self._label = None
		self._format = None

	def getCountry(self):
		"""Returns the country a release took place.

		@note: Due to a server limitation, the web service does not
		return country IDs for release collection queries. This only
		affects the L{musicbrainz2.webservice.Query.getReleases} query.

		@return: a string containing an ISO-3166 country code, or None

		@see: L{musicbrainz2.utils.getCountryName}
		"""
		return self._countryId

	def setCountry(self, country):
		"""Sets the country a release took place.

		@param country: a string containing an ISO-3166 country code
		"""
		self._countryId = country

	country = property(getCountry, setCountry,
		doc='The country a release took place.')

	def getCatalogNumber(self):
		"""Returns the catalog number of this release event.

		@return: A string containing the catalog number, or None
		"""
		return self._catalogNumber
	
	def setCatalogNumber(self, catalogNumber):
		"""Sets the catalog number of this release event.
		
		@param catalogNumber: A string containing the catalog number
		"""
		self._catalogNumber = catalogNumber
	
	catalogNumber = property(getCatalogNumber, setCatalogNumber,
		doc='The catalog number of the release event')
		
	def getBarcode(self):
		"""Returns the barcode of this release event.

		@return: A string containing the barcode, or None
		"""
		return self._barcode
	
	def setBarcode(self, barcode):
		"""Sets the barcode of this release event.
		
		@param barcode: A string containing the barcode
		"""
		self._barcode = barcode
	
	barcode = property(getBarcode, setBarcode,
		doc='The barcode of the release event')
		
	def getLabel(self):
		"""Returns a L{Label} object for the label associated with this release.
		
		@return: a L{Label} object, or None
		"""
		return self._label

	def setLabel(self, label):
		"""Sets the label of this release event.
		
		@param label: A L{Label} object
		"""
		self._label = label

	label = property(getLabel, setLabel, doc='The label of the release')

	def getDate(self):
		"""Returns the date a release took place.

		@return: a string containing a date
		"""
		return self._dateStr

	def setDate(self, dateStr):
		"""Sets the date a release took place.

		@param dateStr: a string containing a date
		"""
		self._dateStr = dateStr

	date = property(getDate, setDate, doc='The date a release took place.')

	def getFormat(self):
		"""Returns the format of the release medium.

		@return: a string containing a URI, or None
		"""
		return self._format

	def setFormat(self, format):
		"""Sets the format of the release medium.

		@param format: a string containing a URI
		"""
		self._format = format

	format = property(getFormat, setFormat,
		doc='The format of the release medium.')


class CDStub(object):
	"""Represents a CD Stub"""

	def __init__(self, disc):
		"""Constructor.

		@param disc: a L{Disc} object to create this CD Stub from
		"""
		assert isinstance(disc, Disc), 'musicbrainz2.model.Disc expected'
		self._disc = disc
		self._tracks = [ ]
		self._title = ""
		self._artist = ""
		self._barcode = ""
		self._comment = ""

	def setTitle(self, title):
		"""Sets the title of this release.

		@param title: a string containing the title
		"""
		self._title = title

	def getTitle(self):
		"""Returns the title of this release.

		@return: a string containing the title
		"""
		return self._title

	title = property(getTitle, setTitle,
	       doc='The title of the release')

	def setArtist(self, artist):
		"""Sets the artist of this release.

		@param artist: a string containing the artist
		"""
		self._artist = artist

	def getArtist(self):
		"""Returns the artist of this release.

		@return: a string containing the artist
		"""
		return self._artist

	artist = property(getArtist, setArtist,
		doc='The artist of the release')

	def setComment(self, comment):
		"""Sets the comment for this release.

		@param comment: a string containing the comment
		"""
		self._comment = comment

	def getComment(self):
		"""Returns the comment for this release.

		@return: a string containing the comment
		"""
		return self._comment

	comment = property(getComment, setComment,
		 doc='Comment for the release (optional)')

	def setBarcode(self, barcode):
		"""Sets the barcode of this release.

		@param barcode: a string containing the barcode
		"""
		self._barcode = barcode

	def getBarcode(self):
		"""Returns the barcode of this release.

		@return: a string containing the barcode
		"""
		return self._barcode

	barcode = property(getBarcode, setBarcode,
		 doc='Barcode for the release (optional)')

	def addTrack(self, title, artist=''):
		"""Add a track to this release

		@param title: a string containing the title of the track
		@param artist: a string containing the artist of the track, 
		               if different to the album artist
		"""
		self._tracks.append((title, artist))

	def getTracks(self):
		"""Return all the tracks on the release.

		@return: a list of tuples containing (title, artist) pairs
		         for each track
		"""
		return self._tracks

	tracks = property(getTracks, doc='The tracks of the release.')

class Disc(object):
	"""Represents an Audio CD.

	This class represents an Audio CD. A disc can have an ID (the
	MusicBrainz DiscID), which is calculated from the CD's table of
	contents (TOC). There may also be data from the TOC like the length
	of the disc in sectors, as well as position and length of the tracks.

	Note that different TOCs, maybe due to different pressings, lead to
	different DiscIDs. Conversely, if two different discs have the same
	TOC, they also have the same DiscID (which is unlikely but not
	impossible). DiscIDs are always 28 characters long and look like this:
	C{'J68I_CDcUFdCRCIbHSEbTBCbooA-'}. Sometimes they are also referred
	to as CDIndex IDs.

	The L{MusicBrainz web service <musicbrainz2.webservice>} only returns
	the DiscID and the number of sectors. The DiscID calculation function 
	L{musicbrainz2.disc.readDisc}, however, can retrieve the other
	attributes of L{Disc} from an Audio CD in the disc drive.
	"""
	def __init__(self, id_=None):
		"""Constructor.

		@param id_: a string containing a 28-character DiscID 
		"""
		self._id = id_
		self._sectors = None
		self._firstTrackNum = None
		self._lastTrackNum = None
		self._tracks = [ ]

	def getId(self):
		"""Returns the MusicBrainz DiscID.

		@return: a string containing a 28-character DiscID 
		"""
		return self._id

	def setId(self, id_):
		"""Sets the MusicBrainz DiscId.

		@param id_: a string containing a 28-character DiscID
		"""
		self._id = id_

	id = property(getId, setId, doc="The MusicBrainz DiscID.")

	def getSectors(self):
		"""Returns the length of the disc in sectors.

		@return: the length in sectors as an integer, or None
		"""
		return self._sectors

	def setSectors(self, sectors):
		"""Sets the length of the disc in sectors.

		@param sectors: the length in sectors as an integer
		"""
		self._sectors = sectors

	sectors = property(getSectors, setSectors,
		doc="The length of the disc in sectors.")

	def getFirstTrackNum(self):
		"""Returns the number of the first track on this disc.

		@return: an int containing the track number, or None
		"""
		return self._firstTrackNum

	def setFirstTrackNum(self, trackNum):
		"""Sets the number of the first track on this disc.

		@param trackNum: an int containing the track number, or None
		"""
		self._firstTrackNum = trackNum

	firstTrackNum = property(getFirstTrackNum, setFirstTrackNum,
		doc="The number of the first track on this disc.")

	def getLastTrackNum(self):
		"""Returns the number of the last track on this disc.

		@return: an int containing the track number, or None
		"""
		return self._lastTrackNum

	def setLastTrackNum(self, trackNum):
		"""Sets the number of the last track on this disc.

		@param trackNum: an int containing the track number, or None
		"""
		self._lastTrackNum = trackNum

	lastTrackNum = property(getLastTrackNum, setLastTrackNum,
		doc="The number of the last track on this disc.")

	def getTracks(self):
		"""Returns the sector offset and length of this disc.

		This method returns a list of tuples containing the track
		offset and length in sectors for all tracks on this disc.
		The track offset is measured from the beginning of the disc,
		the length is relative to the track's offset. Note that the
		leadout track is I{not} included.

		@return: a list of (offset, length) tuples (values are ints)
		"""
		return self._tracks

	tracks = property(getTracks,
		doc='Sector offset and length of all tracks.')

	def addTrack(self, track):
		"""Adds a track to the list.
		
		This method adds an (offset, length) tuple to the list of
		tracks. The leadout track must I{not} be added. The total
		length of the disc can be set using L{setSectors}.

		@param track: an (offset, length) tuple (values are ints)

		@see: L{getTracks}
		"""
		self._tracks.append(track)


class AbstractAlias(object):
	"""An abstract super class for all alias classes."""
	def __init__(self, value=None, type_=None, script=None):
		"""Constructor.

		@param value: a string containing the alias
		@param type_: a string containing an absolute URI
		@param script: a string containing an ISO-15924 script code
		"""
		self._value = value
		self._type = type_
		self._script = script

	def getValue(self):
		"""Returns the alias.

		@return: a string containing the alias
		"""
		return self._value

	def setValue(self, value):
		"""Sets the alias.

		@param value: a string containing the alias
		"""
		self._value = value

	value = property(getValue, setValue, doc='The alias value.')

	def getType(self):
		"""Returns the alias type.

		@return: a string containing an absolute URI, or None 
		"""
		return self._type

	def setType(self, type_):
		"""Sets the alias type.

		@param type_: a string containing an absolute URI, or None
		"""
		self._type = type_

	type = property(getType, setType, doc='The alias type.')

	def getScript(self):
		"""Returns the alias script.

		@return: a string containing an ISO-15924 script code
		"""
		return self._script

	def setScript(self, script):
		"""Sets the alias script.

		@param script: a string containing an ISO-15924 script code
		"""
		self._script = script

	script = property(getScript, setScript, doc='The alias script.')


class ArtistAlias(AbstractAlias):
	"""Represents an artist alias.

	An alias (the I{alias value}) is a different representation of an
	artist's name. This may be a common misspelling or a transliteration
	(the I{alias type}).

	The I{alias script} is interesting mostly for transliterations and
	indicates which script is used for the alias value. To represent the
	script, ISO-15924 script codes like 'Latn', 'Cyrl', or 'Hebr' are used.
	"""
	pass


class LabelAlias(AbstractAlias):
	"""Represents a label alias.

	An alias (the I{alias value}) is a different representation of a
	label's name. This may be a common misspelling or a transliteration
	(the I{alias type}).

	The I{alias script} is interesting mostly for transliterations and
	indicates which script is used for the alias value. To represent the
	script, ISO-15924 script codes like 'Latn', 'Cyrl', or 'Hebr' are used.
	"""
	pass


class User(object):
	"""Represents a MusicBrainz user."""

	def __init__(self):
		"""Constructor."""
		self._name = None
		self._types = [ ]
		self._showNag = None

	def getName(self):
		"""Returns the user name.

		@return: a string containing the user name
		"""
		return self._name

	def setName(self, name):
		"""Sets the user name.

		@param name: a string containing the user name
		"""
		self._name = name

	name = property(getName, setName, doc='The MusicBrainz user name.')

	def getTypes(self):
		"""Returns the types of this user.

		Most users' type list is empty. Currently, the following types
		are defined:

		 - 'http://musicbrainz.org/ns/ext-1.0#AutoEditor'
		 - 'http://musicbrainz.org/ns/ext-1.0#RelationshipEditor'
		 - 'http://musicbrainz.org/ns/ext-1.0#Bot'
		 - 'http://musicbrainz.org/ns/ext-1.0#NotNaggable'

		@return: a list of strings containing absolute URIs
		"""
		return self._types

	types = property(getTypes, doc="The user's types.")

	def addType(self, type_):
		"""Add a type to the list of types.

		@param type_: a string containing absolute URIs

		@see: L{getTypes}
		"""
		self._types.append(type_)

	def getShowNag(self):
		"""Returns true if a nag screen should be displayed to the user.

		@return: C{True}, C{False}, or None
		"""
		return self._showNag

	def setShowNag(self, value):
		"""Sets the value of the nag screen flag.

		If set to C{True}, 

		@param value: C{True} or C{False}

		@see: L{getShowNag}
		"""
		self._showNag = value

	showNag = property(getShowNag, setShowNag,
		doc='The value of the nag screen flag.')

# EOF