|
Adam,
Did
you get a solution for this yet?
The
problem you are having is the value object has an aggregate. This would
happen in either a compose or aggregate. And since your object is
self-referential, it seems like you are stuck if you want an aggregate on this
field, all or nothing.
The
solution is to define multiple value objects for the bean. I always define
two. One header from a typical class has these two
lines:
* @ejb:value-object name="GL_AccountLight"
match="light"
* @ejb:value-object name="GL_AccountFull"
match="*"
Then, each persistent field (but NOT
relationships) get a tag of:
*
@ejb:value-object match="light"
Then
finally, you have to change your relation aggregate to return a xxxLight
value.
What
happens then is you will get the node and one parent object, but without the
relation in the parent because the parent is a "light" object. This
"breaks the chain" in a recursive load into the value
object.
I
generally think this is important in general if you start using aggregates or
composites in VO's. In a highly normalized database with a lot
of relations and aggregates, you inevitably end up loading way more data
than you want unless you use such a technique. This may be one
of the reasons they are hard to use, it took me a few days to grasp.
But I could be a dim bulb, what do I know... :-)
HTH,
-b
I'm having an issue with defining a CMR on an
object that has children/parents of itself
ie, table form:
node_id(tsn), node_name,
parent_node_id (parent_tsn)
/**
*
@ejb.interface-method
*
@ejb.relation
*
name="node-has-children"
*
role-name="node"
*
target-ejb="Unit"
*
target-role-name="children"
*
*
@jboss.target-relation
*
related-pk-field="tsn"
*
fk-column="parent_tsn"
*
*
@ejb.relation
*
name="node-has-children"
*
role-name="children"
*
*
@ejb.value-object
*
aggregate="com.foo.UnitValue"
*
aggregate-name="ChildNode"
*
members="com.foo.UnitLocal"
*
members-name="UnitValue"
*
relation="external"
*
type="Collection"
*/
Is this the correct way to do this?
It works.. but it works too well. Once it loads the children for
the object, it continues to load the children for each of those children, and
then the children of all of those children... until it runs out of
data.
Is the value object the problem? I'm
using aggregate rather than compose, as the objects aren't responsible for
creating each other (this is a static table).
Is this a factor of the way I've defined my
relationship, or an issue with CMR or my app server? (I'm using JBoss
3.0.6). Is there a tag I can add to control the read depth? I've
tried using the read-ahead strategy tag, but that doesn't seem to do anything
(even when I set it to "none").
I'm sorry if this isn't the right place.. just
checking all possibilities (I've posted on the java forums, too).
Thanks for all help!
| 