gs1-7.java

public static final DBObject toDBObject(Person person) {
    return new BasicDBObject("_id", person.getId())
                     .append("name", person.getName())
                     .append("address", new BasicDBObject("street", person.getAddress().getStreet())
                                                  .append("city", person.getAddress().getTown())
                                                  .append("phone", person.getAddress().getPhone()))
                     .append("books", person.getBookIds());
}