Hibernate Criteria for tables with more than one relationsship

Question

I've got a database with two tables (City, Country) and two relations between them.

The first one is the "a country has multiple cities" relation.

select * from City inner join Country on(code=countrycode);

The second one is the "a country has one capital" relation.

select * from City inner join Country on(capital=id);

Hibernate criterias work fine for the first relation, e.g.

Criteria criteria = session.createCriteria(City.class);
List<City> = criteria
                .createCriteria("countrycode")
                .add(Restrictions.eq("continent", continent))
                .list();

But how can I create an Hibernate criteria to retrieve a list of capitals? The second relation is unmapped. Does Hibernate support this kind of relationship?

The City class:

@Entity
public class City {

    @Id
    @Column(name = "ID", updatable = false, nullable = false)
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    ...

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "countrycode", nullable = false)
    private Country countrycode;

    ...

The Country class:

@Entity
public class Country {

    @Id
    private String code;

    @OneToMany(targetEntity = City.class, mappedBy = "countrycode")
    private Set<City> cities;

    private Integer capital;

    ...

Answer 1

The information whether or not the city is capital of any country has to be within City. Add a boolean field to City an query it like that:

List<City> = session.createCriteria(City.class)
                .createCriteria("countrycode")
                .add(Restrictions.eq("continent", continent))
                .add(Restrictions.eq("capital", true))
                .list();