public List<Tag> tags() {
return (myTags != null) ? Collections.unmodifiableList(myTags) : Collections.<Tag>emptyList();
}
public BookCollection(BooksDatabase db, List<String> bookDirectories) {
myDatabase = db;
BookDirectories = Collections.unmodifiableList(new ArrayList<String>(bookDirectories));
}
public List<Author> authors() {
return (myAuthors != null)
? Collections.unmodifiableList(myAuthors)
: Collections.<Author>emptyList();
}