I just bumped into a small problem. I have a couple of classes that all have a different field mapped to the identifier property. I'm using <property formula="otherFieldName"> so hibernate will understand this.

Similar logic is implemented in the classes.

I have two problems with this.

A. Hibernate wants a setter for the generated property, eventhough my javaclasses have their own logic to compute its value. I worked around this by adding a setter that actually sets nothing. but I don't like this as it is ugly.

B. with Inheritance there is no way to override the way this property works. I'd like to be able to use a different field or formula in child classes, but I don't see a way to do this in Hibernate mappings. Hibernate will always use the formula of the parent class which is undesirable. Hibernate should allow to override the formula of a property in subclasses as long as the types remain the same.

I need this because I want to be able to query on the baseclass with a certain value assigned to this property so my baseclass has an abstract getter that must be overridden by the child classes. The children handle this by returning a different field from their own private members.

For example:

Parent:
a getIdentifier()

Child 1
p getEmail()
p getIdentifier (returns getEmail)

Child 2
p getUsername()
p getIdentifier (returns getUsername)

Is there a way to do this without having to redundantly save the identifier field or by having a redundant setter for the identifier field?

Why do you map this property at all? Just don't map it and in your getIdentifier() method do something like "return getUsername()"

because I want to use a hibernate query that does

from users a where a.identifier=:ident

and I cannot do that unless I map the value right?

Regardless of why; it would be nice if dynamic properties could be overwritten by inheritance as it is possible in normal Java objects.

Oh well, if you insist to do that: You can implement your own PropertyAccessor for the property, which does nothing on set.

PS: you know that you can just map the username as the identifier and still do "where x.id = ? " in your HQL?

I tried but it does not work.

The point is, I have an abstract base class with a getIdentifier function. Every class that inherits from that will provide its own implementation. I want to be able to query against this so I set up the following:

user (abstract)
- getIdentifier (not mapped in hibernate)

subuser1
- getIdentifier (mapped in hibernate using formula to give the email address)

subuser2
- getIdentifier (mapped in hibernate using formula to give the username)

This works as long as you query for the exact subtype, but a query against just user will fail.

I tried this next

user (abstract)
- getIdentifier (mapped as formula returning "")

subuser1
- getIdentifier (mapped in hibernate using formula to give the email address)

subuser2
- getIdentifier (mapped in hibernate using formula to give the username)

This allows to query against the general user type, but all queries for identifier return "", because the base property formula overrides those of its children.

From an OO perspective this should not happen and as formula properties are no static members, but dynamic fields (more like functions) I want to be able to alter their implementation for each subclass.

The reason I don't want to map both the identifier and the username and the email column is that this would give me redundant data in the database as the email and username field are already saved. But I'll stick to this path as I see no other working alternative at this point.