JPA Criteria to query hierarchy of child objects - jpa

Question

I have two tables that are represented by following entity object hierarchies:
#Entity
#Table(name = Transport.TABLE_NAME)
#DiscriminatorColumn(name="transport_type", discriminatorType = DiscriminatorType.INTEGER)
#Inheritance(strategy=InheritanceType.SINGLE_TABLE)
public abstract class Transport {
...
private Date departure;
}
#Entity
#DiscriminatorValue("1")
public class Bicycle extends Transport {
...
#OneToOne(mappedBy = "transport", fetch = FetchType.LAZY)
private BikePassenger passenger;
}
#Entity
#DiscriminatorValue("2")
public class Car extends Transport {
...
#OneToMany(mappedBy = "transport", fetch = FetchType.EAGER)
private List<CarPassanger> passengers;
}
#Entity
#Table(name = Passenger.TABLE_NAME)
#DiscriminatorColumn(name="passenger_type", discriminatorType = DiscriminatorType.INTEGER)
#Inheritance(strategy=InheritanceType.SINGLE_TABLE)
public abstract class Passenger {
...
private int passengerGUID;
}
#Entity
#DiscriminatorValue("1")
public class BicyclePassenger extends Passenger {
...
#OneToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "transportid")
private Bicycle transport;
}
#Entity
#DiscriminatorValue("2")
public class CarPassenger extends Passenger {
...
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "transportid")
private Car transport;
}
Now using JPA Criteria API (or at least JPA) how do I:
Get all transports that have passengers with specific passengerGUID?
Group transports (along with passengers) by departure date?
As I see it #1 should have nice solution but I was able to get out only with 2 subselects for each subtype. Which looks ugly to me.
And finally third question - is it good model at all? From OOP point of view to me it looks ok, but from ORM point of view and easiness of queries it looks not so good...
p.s. I'm using hibernate JPA 2.1