Hi All,

I'm having a problem passing a collection to the constructor in a select clause. I have two classes which look minimally like this. (getters and setters omitted for brevity)

@Entity
public class User{

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private int id;

private String username;

@ManyToOne(optional=false,fetch = FetchType.LAZY)
private Organisation company;

@ManyToMany
private Set<SecurityGroup> securityGroups = new HashSet<SecurityGroup>();

public User(String username, Set<SecurityGroup> securityGroups){
this.username = username;
this.securityGroups = securityGroups;
}

}

@Entity
public class SecurityGroup{

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private int id;

private String name;

@ManyToMany (mappedBy="securityGroups")
private List<User> users;

}

I have lots of other properties in the User that I don't want to fetch with each query. So I'm trying to minimize the amount of data loaded.
Here are the different query scenarios and exceptions I get

1. When I execute the following query:
select new com.test.User(o.username, o.securityGroups) from User o left join o.securityGroups s where o.company.id=:companyId

I get the following exception:
org.hibernate.util.JDBCExceptionReporter:101 - You have an error in your SQL syntax

(this is a named query with companyId set appropriately. Everything works fine if I don't pass the securityGroups in the constructor)

2. When the query is changed to:
select new com.test.User(o.username, s) from User o left join o.securityGroups s where o.company.id=:companyId

I get this exception at deployment time:
org.hibernate.hql.ast.QuerySyntaxException: Unable to locate appropriate constructor on class [com.test.User]

3. When the constructor is changed to
public User(String username, Object securityGroups)

The application deploys alright, but I get this exception when the query is executed:
java.lang.IllegalArgumentException: org.hibernate.QueryException: could not instantiate class [com.test.User] from tuple

However following example in the hibernate documentation suggests that a collection can be passed in a constructor specified in a select clause:
select new Family(mother, mate, offspr) from DomesticCat as mother join mother.mate as mate left join mother.kittens as offspr

I guess my question is: is what I'm trying to do supported and if so, what am I doing wrong?

Any help is very much appreciated! Thanks.