/** Called by the providers when the details of an album have been updated. */
  @Override
  public void onAlbumUpdate(ProviderIdentifier provider, final Album a) throws RemoteException {
    if (a == null) {
      Log.w(TAG, "Provider returned a null album");
      return;
    }

    Album cached = mCache.getAlbum(a.getRef());
    boolean modified = false;

    // See IProviderCallback.aidl in providerlib for more info about the logic of updating
    // the Album objects
    if (cached == null) {
      mCache.putAlbum(provider, a);
      cached = a;
      modified = true;
    } else if (!cached.isLoaded() || !cached.isIdentical(a)) {
      cached.setName(a.getName());
      cached.setYear(a.getYear());
      cached.setIsLoaded(a.isLoaded());
      cached.setProvider(a.getProvider());

      if (cached.getSongsCount() != a.getSongsCount()) {
        Iterator<String> songsIt = a.songs();
        while (songsIt.hasNext()) {
          String songRef = songsIt.next();
          cached.addSong(songRef);
        }
      }

      modified = true;
    }

    if (cached.getProvider() == null) {
      Log.e(TAG, "Provider for " + cached.getRef() + " is null!");
    }

    if (modified) {
      // Add the album to each artist of the song (once)
      Iterator<String> songs = a.songs();

      while (songs.hasNext()) {
        String songRef = songs.next();
        Song song = retrieveSong(songRef, a.getProvider());

        if (song != null && song.isLoaded()) {
          String artistRef = song.getArtist();
          if (artistRef != null) {
            Artist artist = retrieveArtist(artistRef, song.getProvider());

            if (artist != null) {
              artist.addAlbum(a.getRef());
            } else {
              if (DEBUG) Log.e(TAG, "Artist is null!");
            }
          }
        } else {
          if (DEBUG) Log.e(TAG, "Song is null!");
        }
      }

      postAlbumForUpdate(cached);
    }
  }