@Override
public Image setAlbum(Album album) {
checkNotNull(album, "album must not be null");
- checkNotNull(album.getSone().equals(getSone()), "album must belong to the same Sone as this image");
+ checkState(album.getSone().equals(getSone()), "album must belong to the same Sone as this image");
this.album = album;
return this;
}