CODEWITHSUNDEEP
hibernatejpa-2.0criteria-api
Pumuckline
Pumuckline

Reputation: 637

How to query for a M:N relationship using enums with CriteriaBuilder

I am curently working on a Company entity which contains a List of Area enum values. These are the areas, the company is working in. They are mapped as @ElementCollection.

@Entity
public class Company {

  @ElementCollection
  @CollectionTable(name = "company2area")
  @Enumerated(EnumType.STRING)
  private List<Area> areas = new ArrayList<Area>();

  ...
}

Area is a simple enum, containing the available areas.

 public enum Area {
    ASIA,
    AMERICA,
    EUROPE;
}

I tried to query for all companies that are currently working in ASIA and AMERICA like this:

CriteriaQuery<Company> query = this.entityManager.getCriteriaBuilder()
                                             .createQuery(Company.class);
query.where(query.from(Company.class)
        .get("areas")
        .in(Arrays.asList(Area.ASIA, Area.AMERICA)));
List<Company> result = entityManager.createQuery(q)
                                    .getResultList();

But all I got is an exception:

Caused by: java.lang.IllegalArgumentException: Parameter value [ASIA]
did not match expected type [java.util.Collection]  at
org.hibernate.ejb.AbstractQueryImpl.validateParameterBinding(AbstractQueryImpl.java:375)
    at
org.hibernate.ejb.AbstractQueryImpl.registerParameterBinding(AbstractQueryImpl.java:348)
    at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:375)     at
org.hibernate.ejb.criteria.CriteriaQueryCompiler$1$1.bind(CriteriaQueryCompiler.java:195)
    at
org.hibernate.ejb.criteria.CriteriaQueryCompiler.compile(CriteriaQueryCompiler.java:241)
    at
org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:587)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)  at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)     at
org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
    at $Proxy61.createQuery(Unknown Source)     ... 29 more

What am I doing wrong? Is there a special trick about the enums?

I'm well aware of the question How to query an M:N relationship with JPA2? I asked some months ago. Unfortunately, the solution from there does not work with enums.

Thanks for your help. :)

Edit:

Here's the description of my MySQL database:

create table company2area (
    Company_fk bigint not null,
    areas varchar(255)
) ENGINE=InnoDB;

create table company (
    id bigint not null auto_increment,
    fullName varchar(255),
    ...,
    primary key (id)
) ENGINE=InnoDB;

alter table company2area 
    add index FK52BA7162CE087250 (Company_fk), 
    add constraint FK52BA7162CE087250 
    foreign key (Company_fk) 
    references company (id);

Upvotes: 6

Views: 2141

Answers (1)

Pumuckline
Pumuckline

Reputation: 637

It works, if I join the tables explicitly:

query.where(query.from(Company.class)
    .join("areas", JoinType.INNER)
    .in(Arrays.asList(Area.ASIA, Area.AMERICA)));

As far as I thought, both ways should result in the same query as inner join is the default, but obviously, only this one here works.

Upvotes: 4

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