+public interface Album extends Identified, Fingerprintable {
+
+ /** Function that flattens the given album and all albums beneath it. */
+ Function<Album, List<Album>> FLATTENER = new Function<Album, List<Album>>() {
+
+ @Override
+ @Nonnull
+ public List<Album> apply(Album album) {
+ if (album == null) {
+ return emptyList();
+ }
+ List<Album> albums = new ArrayList<>();
+ albums.add(album);
+ for (Album subAlbum : album.getAlbums()) {
+ albums.addAll(FluentIterable.from(ImmutableList.of(subAlbum)).transformAndConcat(FLATTENER).toList());
+ }
+ return albums;
+ }
+ };