Populating only part of an Object

vinayb · **Joined:** Thu May 28, 2009 10:25 am **Posts:** 21

Is it possible to dynamically specify (via the query) which parts of the object are populated .

eg. consider a class

Code:

public class Person {
long id;
String name;
String age;
List<Address> addresses;
List<Long> phoneNumbers; 
Company company
}

Is there a way I can chose to populate ONLY one or more (as desired) fields in the query (sort of like dynamic lazy loading)? If I use projections or select Person.a, Person.b ... type syntax, I get a list of Object arrays (which is technically what I want), but I'd really like to be able to cast to a Person object in the query

I looked at projection lists and they are close but still end up with a list of Object arrays.
Thanks

sanne.grinovero · **Posted:** Tue Oct 13, 2009 4:17 am

you can use constructors in HQL, something like

Code:

new Person(person.name, person.age) from Person person where ...

provided you add an appropriate constructor to Person class (and don't forget to explicitly declare the no-arguments constructor too).

Keep in mind that the constructed entity is not managed: you can't lazy load non initialized fields after this kind of loading.

vinayb · **Joined:** Thu May 28, 2009 10:25 am **Posts:** 21

Thanks, that worked.

Though I think it may introduce a new issue. See viewtopic.php?f=1&t=1001487