Annotation Type HQL
-
@Target(METHOD) @Retention(CLASS) @Incubating public @interface HQL
Identifies a method of an abstract class or interface as defining the signature of a method which is used to execute the given HQL query, with an implementation generated automatically by the Hibernate Metamodel Generator.For example:
public interface Books { @HQL("where isbn = :isbn") Book findBookByIsbn(String isbn); @HQL("where title like ?1 order by title offset ?3 fetch first ?2 rows only") List<Book> findBooksByTitleWithPagination(String title, int max, int start); @HQL("where title like ?1") TypedQuery<Book> createBooksByTitleQuery(String title); }
The Metamodel Generator automatically creates an "implementation" of these methods in the static metamodel class
Books_
. The generated methods may be called according to the following protocol:Book book = Books_.findBookByIsbn(session, isbn); List<Book> books = Books_.findBooksByTitleWithPagination(session, pattern, 10, 0);
Notice the extra parameter of type
EntityManager
at the start of the parameter list.Alternatively, the type to which the annotated method belongs may also declare an abstract method with no parameters which returns one of the types
EntityManager
,Session
,StatelessSession
, orMutiny.Session
, for example:EntityManager entityManager();
In this case:- the generated method is no longer
static
, - the generated method will use this method to obtain the
session object, instead of having a parameter of type
EntityManager
, and - the generated static metamodel class will actually implement
the type which declares the method annotated
@SQL
.
Thus, the generated methods may be called according to the following protocol:
Books books = new Books_(session); Book book = books.findBookByIsbn(isbn); List<Book> books = books.findBooksByTitleWithPagination(pattern, 10, 0);
This is reminiscent of traditional DAO-style repositories.
For a
select
query, the return type of an annotated method must be:- an entity type,
List
,io.smallrye.mutiny.Uni
, when used with Hibernate Reactive,Query
,SelectionQuery
,Query
, orTypedQuery
.
For an
insert
,update
, ordelete
query, the return type of the annotated method must beint
,boolean
, orvoid
.The method parameters must match the parameters of the HQL query, either by name or by position:
- an ordinal query parameter of form
?n
is matched to the nth parameter of the method, and - a named query parameter of form
:name
is matched to the method parametername
.
As an exception, the method may have:
- a parameter of type
EntityManager
,Session
,StatelessSession
, orMutiny.Session
, - a parameter with type
Page
, and/or - a parameter with type
Order<? super E>
,List<Order<? super E>>
, orOrder<? super E>...
(varargs) whereE
is the entity type returned by the query.
For example:
@HQL("where title like :title) List<Book> findBooksByTitleWithPagination(String title, Page page, Order<Book> order);
Queries specified using this annotation are always validated by the Metamodel Generator, and so it isn't necessary to specify the
CheckHQL
annotation. - the generated method is no longer
-
-
Element Detail
-
value
String value
-
-