@javax.persistence.OrderBy + Set does not order results

youngm77 · **Joined:** Thu Aug 26, 2004 9:23 pm **Posts:** 71

@ManyToMany(fetch=FetchType.EAGER)
@JoinTable(name="ANIMAL_COUNTRY",
joinColumns=@JoinColumn(name="ANIMAL_ID"),
inverseJoinColumns=@JoinColumn(name="COUNTRY_ID"))
@Cache(usage=CacheConcurrencyStrategy.TRANSACTIONAL)
@javax.persistence.OrderBy("name")
private Set<Country> countries;

Does not order the countries by name. If I change the Set to a List it correctly ordered. Any ideas? Does Hibernate fail to use a LinkedHashSet if the @javax.persistence.OrderBy annotation is used?

Mike

impairator · **Joined:** Wed Jan 17, 2007 6:42 pm **Posts:** 1

Hi Mike,

I think the reason you're getting an unsorted collection with a Set and a sorted one with a List is just because they're naturally unsorted or sorted !

To get a sorted collection you have to use a SortedSet (e.g. a TreeSet)
or a List or even an array..

In your case,

private Set<Country> countries;

must be something like

private SortedSet<Country> countries = new TreeSet<Country>();

(of course, you can omit the assignment if you don't need it...)

Hope it helps !

bye

Andrea

youngm77 · **Joined:** Thu Aug 26, 2004 9:23 pm **Posts:** 71

Quote:

I think the reason you're getting an unsorted collection with a Set and a sorted one with a List is just because they're naturally unsorted or sorted !

I wouldn't say that Sets are naturally unsorted but I would say Lists are naturally sorted. The hibernate docs say that if I use a org.hibernate.annotations.OrderBy then Hibernate will internally use a LinkedHashSet which is an ordered set. However Hibernate doesn't appear to use a LinkedHashSet if I use the javax.persistence.OrderBy annotation.

I'd like to stay as close to JPA as possible just thought it strange that hibernate could provide ordered (not sorted) Set functionality with the hibernate @OrderBy annotation but not do the same with the JPA @OrderBy annotation. But maybe there is some strange JPA spec requirement that says the JPA @OrderBy annotation should only work on a List?

Mike

youngm77 · **Joined:** Thu Aug 26, 2004 9:23 pm **Posts:** 71

In fact reading through the spec (section 9.1.26) it just says "ordering of the elements of a collection" so I would think Set should be included in that.

Rhodan · **Joined:** Mon Sep 12, 2005 3:27 am **Posts:** 48

But the hibernate-annotation doc also states:

Quote:

@OrderBy currently works only on collections having no association table

see documentation

youngm77 · **Joined:** Thu Aug 26, 2004 9:23 pm **Posts:** 71

Ah, good find. Thanks.

Mike

emmanuel · **Posted:** Sun Jan 21, 2007 8:49 pm

The doc was not uptodate,
@o.h.a.OrderBy and j.p.OrderBy lead to the same underlying ordering mechanism, so the behavior should be the same.

Can you check if you have a LinkedHashSet underneath the PersistenceSet (through a debugger)

youngm77 · **Joined:** Thu Aug 26, 2004 9:23 pm **Posts:** 71

When I debug it appears that when using j.p.OrderBy the PersistentSet.set is a HashSet and not a LinkedHashSet. Here is my Animal and Country models just to make sure it is not some kind of dumb annotation problem on my end:

Animal trimmed getters and setters

Code:

@Entity
@Cache(usage = CacheConcurrencyStrategy.TRANSACTIONAL)
@NamedQueries({
   @NamedQuery(name=Animal.QUERY_GET_ALL_ANIMALS_AS_SELECT_ITEMS, query="select new javax.faces.model.SelectItem(a, a.name) from Animal a")
})
@SuppressWarnings("serial")
public class Animal implements Serializable {
   public static final String QUERY_GET_ALL_ANIMALS_AS_SELECT_ITEMS = "getAllAnimalsAsSelectItems";

   @Id @GeneratedValue
   private Long id;
    @Temporal(TemporalType.TIMESTAMP)
    @Column(name="CREATED", nullable = false, updatable = false)
   private Date created = new Date();
   @Column(unique=true, nullable=false)
    private String name;
    @Enumerated(EnumType.STRING)
    private Gender gender;
    @Column(length=4000)
    private String description;
    private String imageUrl;
    @Column(nullable=false)
    private double price;
    private Date dateOfBirth;
    @ManyToOne(fetch=FetchType.LAZY)
    private Classification classification;
    @ManyToMany(fetch=FetchType.EAGER)
    @JoinTable(name="ANIMAL_COUNTRY",
          joinColumns=@JoinColumn(name="ANIMAL_ID"),
          inverseJoinColumns=@JoinColumn(name="COUNTRY_ID"))
    @Cache(usage=CacheConcurrencyStrategy.TRANSACTIONAL)
    @BatchSize(size=10)
    @OrderBy("name")
    private Set<Country> countries;
    @SuppressWarnings("unused")
   @Version
    private Long version;

Country

Code:

@Entity
@Cache(usage = CacheConcurrencyStrategy.READ_ONLY)
@SuppressWarnings("serial")
@BatchSize(size=25)
@NamedQueries({
   @NamedQuery(name=Country.QUERY_ALL_COUNTRY_IDS_AS_SELECT_ITEMS, query="select new javax.faces.model.SelectItem(c.id, c.name) from Country c",
         hints=@QueryHint(name="org.hibernate.cacheable", value="true")),
   @NamedQuery(name=Country.QUERY_ALL_COUNTRIES_AS_SELECT_ITEMS, query="select new javax.faces.model.SelectItem(c, c.name) from Country c",
         hints=@QueryHint(name="org.hibernate.cacheable", value="true"))
})
public class Country implements Serializable {
   public static final String QUERY_ALL_COUNTRY_IDS_AS_SELECT_ITEMS = "allCountryIdsAsSelectItems";
   public static final String QUERY_ALL_COUNTRIES_AS_SELECT_ITEMS = "allCountriesAsSelectItems";

   @Id @GeneratedValue @Column(updatable=false)
   private Long id; //NOPMD - wheelermm
   @Column(unique=true, nullable=false)
    public String name;
   @Cache(usage=CacheConcurrencyStrategy.TRANSACTIONAL)
    @ManyToMany(mappedBy="countries", fetch=FetchType.EAGER)
    @Fetch(FetchMode.SUBSELECT)
    @BatchSize(size=20)
    public Set<Animal> animals;

emmanuel · **Posted:** Wed Jan 24, 2007 5:10 pm

you're using the latest version, aren't you?
If thisis the case, can you wrap your code and put it in JIRa, I'll need to have a look

youngm77 · **Joined:** Thu Aug 26, 2004 9:23 pm **Posts:** 71

I just upgraded to Hibernate core 3.2.2 (released today) and it appears to have fixed the problem. Possibly related to this issue:

HHH-2274

Thanks,
Mike

emmanuel · **Posted:** Wed Jan 24, 2007 10:48 pm

ah, nice.