I recently raised a feature request which was closed:

http://opensource.atlassian.com/project ... wse/HB-924

Can anyone shed any light on Gavin's comment that there "are other ways to do this"?

Why don't you write you own IdentifierGenerator.

Because the one that comes with Hibernate works perfectly!

I want to get access to a valid newly generated ID so I can derive some property values from it.

I'd imaging there would be other useful applications of

Serializable Session.generateIdentifier(Class component);


Regards,

Niall

I thought about that and the best solutions I came to were:
- use a custom generator if the ID is a CONSTANT + Unique Id
- build the property in a plain getter if the property is build on top of the id.

Session.getIdentifier(Class) is not really OO

Not OO? In what way? Perhaps you would be happier with this?

Session.getIdentifierGenerator(Class);

In any case I worked around this limitation by subclassing IncrementGenerator.

For some reason nobody wants to give a straight answer to this question :).
The real reason is that the getIdentifierGenerator(...).generate(...) needn't
always give the id. For e.g. in MySQL, if generator class is native and
autoincrement is set on the table's primary key following is what hibernate would do
1/ insert the row without setting the id
2/ use MySQL's last_insert_id() function to reterive the id of the row that
was just inserted
3/ set this id on the object and return the id

In such a scenario calls to getIdentifierGenerator(...).generate(...) before inserting a row would return nothing!