My entity classes are following
@Entity
@table
public class User {
@OneToOne
private UserProfile userProfile;
// others
}
@Entity
@Table
public class UserProfile {
@OneToOne
private Country country;
}
@Entity
@Table
public class Country {
@OneToMany
private List<Region> regions;
}
Now I want to get all the user in a particular region. I know the sql but I want to do it by spring data jpa Specification. Following code should not work, because regions is a list and I am trying to match with a single value. How to fetch regions list and compare with single object?
public static Specification<User> userFilterByRegion(String region){
return new Specification<User>() {
@Override
public Predicate toPredicate(Root<User> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
return criteriaBuilder.equal(root.get("userProfile").get("country").get("regions").get("name"), regionalEntity);
}
};
}
Edit: Thanks for the help. Actually I am looking for the equivalent criteria query for the following JPQL
SELECT u FROM User u JOIN FETCH u.userProfile.country.regions ur WHERE ur.name=:<region_name>
Try this. This should work
criteriaBuilder.isMember(regionalEntity, root.get("userProfile").get("country").get("regions"))
You can define the condition for equality by overriding Equals
method(also Hashcode) in Region class