Spring Data JPA, parametrize #EntityGraph in CrudRepository interface - spring

Question

Is it possible with Spring Data JPA to do smth. like this:
public interface UserDao extends CrudRepository<User, Long> {
#EntityGraph(value = :graphName, type = EntityGraph.EntityGraphType.LOAD)
#Query(value = "SELECT DISTINCT u FROM User u")
List<User> findAllWithDetailsByGraphName(#Param(value="graphName") String graphName);
}
to be able to pass the graphName into method at run-time and invoke the load with a need set of collections? This construction is not working, producing compile time error. Any plays around it also failed...
So, I have multiple collections in User class, which I want to load on condition;
#Entity
#Table(name="user")
#NamedEntityGraphs({
#NamedEntityGraph(name = "User.details", attributeNodes = {
#NamedAttributeNode("phones"), #NamedAttributeNode("emails"), #NamedAttributeNode("pets")}),
#NamedEntityGraph(name = "User.phones", attributeNodes =
{#NamedAttributeNode("phones")}),
#NamedEntityGraph(name = "User.emails", attributeNodes =
{#NamedAttributeNode("emails")}),
#NamedEntityGraph(name = "User.pets", attributeNodes =
{#NamedAttributeNode("pets")})
})
public class User {
#Id
#GeneratedValue(strategy= GenerationType.AUTO, generator="native")
#GenericGenerator(name = "native", strategy = "native")
#Column(name="user_id")
private Long userId;
#Column(name="name")
private String name;
// more fields omitted
#OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
private Set<Phone> phones;
#OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
private Set<Email> emails;
#OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
private Set<Pet> pets;
}
Now, I only must declare all the methods implicitly, like this:
#EntityGraph(value = "User.phones", type = EntityGraph.EntityGraphType.LOAD)
#Query(value = "SELECT DISTINCT u FROM User u")
List<User> findAllWithPhones();
Thnaks you for suggestions!

Answer 1

You can define a base JPA repository that accepts the entity graph as a parameter. This is particularly useful in combination with Specifications. Therefore, here follows an example based on Specifications. It's also possible to construct other queries, using different types of arguments.
#NoRepositoryBean
public interface MyBaseRepository<T, ID extends Serializable> extends PagingAndSortingRepository<T, ID> {
T findOne(Specification<T> spec, EntityGraphType entityGraphType, String entityGraphName);
List<T> findAll(Specification<T> spec, Sort sort, EntityGraphType entityGraphType, String entityGraphName);
}
Implement the base repository:
#NoRepositoryBean
public class MyBaseRepositoryImpl<T, ID extends Serializable> extends SimpleJpaRepository<T, ID> implements MyBaseRepository<T, ID> {
private EntityManager em;
public MyBaseRepositoryImpl(JpaEntityInformation<T, ?> entityInformation, EntityManager entityManager) {
super(entityInformation, entityManager);
this.em = entityManager;
}
public MyBaseRepositoryImpl(Class<T> domainClass, EntityManager em) {
super(domainClass, em);
this.em = em;
}
#Override
public T findOne(Specification<T> spec, EntityGraph.EntityGraphType entityGraphType, String entityGraphName) {
TypedQuery<T> query = getQuery(spec, (Sort) null);
query.setHint(entityGraphType.getKey(), em.getEntityGraph(entityGraphName));
return query.getSingleResult();
}
#Override
public List<T> findAll(Specification<T> spec, Sort sort, EntityGraph.EntityGraphType entityGraphType, String entityGraphName) {
TypedQuery<T> query = getQuery(spec, sort);
query.setHint(entityGraphType.getKey(), em.getEntityGraph(entityGraphName));
return query.getResultList();
}
}
Specify the custom base repository:
<jpa:repositories base-package="my.domain" base-class="my.repository.MyBaseRepositoryImpl" />
Extend from custom base repository:
public interface UserRepository extends JpaRepository<User, Long>, MyBaseRepository<User, Long>, JpaSpecificationExecutor<User> {
}
Use the custom repository's method:
Specification mySpecs = ...
List<User> user = picklistRepository.findAll(mySpecs, EntityGraphType.LOAD, "User.phones");