CODEWITHSUNDEEP
javarepositoryjpa-2.0criteria-api
Shinigami
Shinigami

Reputation: 1055

jpa specification with @OneToOne relation

I'd like to use jpa repository with specification

now I have two tables

@Entity
@Table(name="user")
public class User implements Serializable {

private static final long serialVersionUID = 1L;

private Long idUser;

private Area area;

@Id @GeneratedValue(strategy=GenerationType.AUTO)
@Column(name="iduser")
public Long getIdUser() {
return idUser;
}
public void setIdUser(Long idUser) {
this.idUser = idUser;
}

@OneToOne(fetch=FetchType.LAZY)
@JoinColumn(name="idarea")
public Area getArea() {
    return area;
}

public void setArea(Area area) {
    this.area = area;
}

}

and Area Table

@Entity
@Table(name = "area")
public class Area {

@Id @GeneratedValue(strategy=GenerationType.AUTO)
@Column(name="idarea")
private Long idArea;

@Column(name="area_name")
private String areaName;

public Long getIdArea() {
    return idArea;
}

public void setIdArea(Long idArea) {
    this.idArea = idArea;
}

public String getAreaName() {
    return areaName;
}

public void setAreaName(String areaName) {
    this.areaName = areaName;
}

}

Then I have user Repository that extens also JpaSpecificationExecutor 

public interface UserRepository extends   CrudRepository<User,Long>,JpaSpecificationExecutor<User> {
}

Finally I have a simple specification

public class UserSpecification {

public static Specification<User> findByAreaName(final String areaName){
    return new Specification<User>() {

        @Override
        public Predicate toPredicate(Root<User> root,
                CriteriaQuery<?> criteria, CriteriaBuilder cb) {
            return cb.equal(root.<String>get("??????"),areaName);
        }
    };

}

}

So, my question is :What I have to put in "?????" that is the areaName of table area?

Upvotes: 4

Views: 4793

Answers (1)

Christian
Christian

Reputation: 4094

You could try 

return cb.equal((Path<String>) ((Path<Area>) root.get("area")).get("areaName"),areaName);

And you have to make sure, that Area gets loaded, because its lazy.

Edit: As I mentioned in my comment, maybe just try without casting at all.

I have a method for such cases you can adjust for your needs:

@SuppressWarnings("unchecked")
private <T, R> Path<R> getPath(Class<R> resultType, Path<T> root, String path) {
    String[] pathElements = path.split("\\.");
    Path<?> retVal = root;
    for (String pathEl : pathElements) {
        retVal = (Path<R>) retVal.get(pathEl);
    }
    return (Path<R>) retVal;
}

Its called with the dot-notation to get the path. In your case it would be:

getPath(String.class, root, "area.areaName");

Hope it helps!

Upvotes: 8

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