Feed a list with the last value - jpa

Question

I have theses entity and I do this query.
select r from RentAmount r Join r.lodger l join l.bailList b where r.unpaidBalance > 0 and (r.paymentDueDate > :date or r.paymentDueDate is null ) and b.paymentPeriod= order by r.rentAmountId")
Is there a way to feed Lodger.bailList only with the last bail or i would need to loop on every record to get this information?
#Entity
public class RentAmount {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long rentAmountId;
#OneToOne
private Lodger lodger;
}
#Entity
public class Lodger{
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long lodgerId;
#OneToOne(fetch = FetchType.LAZY, mappedBy="lodger")
private RentAmount rentAmount;
#OneToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE}, fetch = FetchType.LAZY, mappedBy = "lodger", orphanRemoval = true)
private List<Bail> bailList;
}
#Entity
public class Bail {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long bailId;
#Enumerated(EnumType.STRING)
private PaymentPeriodEnum paymentPeriod;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "lodger_id")
private Lodger lodger;
}

Answer 1

There are a few options:
One (Non JPA, Hibernate Only)
Ensure the collection is correctly ordered and mark it is as extra lazy. You will have access to the whole collection but accessing of individual items will not trigger a full load.
https://docs.jboss.org/hibernate/orm/3.3/reference/en/html/performance.html
"Extra-lazy" collection fetching: individual elements of the
collection are accessed from the database as needed. Hibernate tries
not to fetch the whole collection into memory unless absolutely
needed. It is suitable for large collections.
The mapping will look like:
#OneToMany(mappedBy = "lodger")
#LazyCollection(LazyCollectionOption.EXTRA)
#OrderBy("theRelevantProperty ASC")
private List<Bail> bailList;
public void getCurrentBail(){
//will only load this item from the database
return bailList.get(bailList.size() - 1);
}
Two (Non JPA, Hibernate Only.)
Use the #Where annotation to filter the collection so that while still #OneToMany, only one element will be accessible.
https://docs.jboss.org/hibernate/stable/annotations/reference/en/html_single/#entity-hibspec-collection
The mapping will look like:
#OneToMany(mappedBy = "lodger")
#Where(clause="some native sql which will filter to include onyl 1item"))
private List<Bail> bailList;
public void getCurrentBail(){
//will be the only item accessible
return bailList.get(0);
}
Three (JPA Compliant)
Would involve creating views at the database level. Various options in this area. If we are only ever interested in the current bail then this view would be similar to option 2 above. Simply point the Bail entity to this view rather than the concrete table:
#Entity
#Table(name = "vw_active_bail")
public class Bail {
}