Hi all,
Here's my architecture (standard enough)
layer 1: jsps -->
layer 2: struts actions -->
layer 3: ejb3 stateless session bean managers -->
layer 4: ejb3 domain objects
I have a one-to-many relationship between User and Order, ie a User has many
Orders.
Now, I want to load the orders lazily. No problem, I specify the fetch type to
be lazy on the relationship.
So, when i get back a user, I don't get his orders.
In order to get all his orders, I code a second method in one of my stateless
session beans to specifically get all the orders for a given user
eg,
public List getOrdersForUser(String userName){
//first get the user for the username
User u = entityManager.find(User.class,userName);
//then call
return user.getOrders();
}
However, when I call this method I am getting the following exception
failed to lazily initialize a collection of role: model.User.orders, no session
or session was closed" when accessing the data of a "one-to-many" relation.
not good.
Now I have read the following post:
http://www.jboss.com/index.html?module=bb&op=viewtopic&t=73005
And in here it discusses the issue of transactions as the possible cause of the
problem.
I was under the impression that as soon as I entered a method in a stateless
session bean, under the hood the hibernate session is re-opened and therefore I
can access any level in the graph that I want. This is what I would expect with
spring/hibernate etc.
Is this not the case with ejb3 ???
Do I have to explicitly set the transaction attribute on all methods to get
this working??
This is really a case of me not understanding the design as I thought I did. I
understand the List will be detatched from the session when I return it back to
the web tier (which is where the exception is being thrown), but the
information is retrieved from the database in the stateless session bean, so
there should be no problem??
please help!
thanks ,
binario
View the original post :
http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3929085#3929085
Reply to the post :
http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=3929085
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