Hello!
I got a problem which is similar to the following posts (no solution yet
provided):
http://www.jboss.com/index.html?module=bb&op=viewtopic&t=88515
http://www.jboss.com/index.html?module=bb&op=viewtopic&t=121044
I have entities which are organized in an inheritance hierarchy (please have a
look a the code below). When i execute a query (please look at the stateful
session bean below) it returns a proxy-object. But it should be an instance of
the concrete entity bean. I am facing this problem only when querying in an
inheritance hierarchy. For "normal" entity beans it works fine.
How can i tell the entity beans in the inheritance hierarchy that the whole
hierarchy should be fetched eager without eager fetching.
I found a (not suitable) workaround when i use the annotation @Proxy(lazy
=false) at base class level. With this annotation i get the concrete instance
of the entity bean (RfAuthProject-instance with id 483 like in the example
below) but all associations of each entity in the hierarchy are eager fetched
too. That's a problem because, it gets really slow.
How can i achieve that only the inheritance hierarchy is fetched and none of
the associations?
Thanks in advance for your help.
kind regards
Patrik
ps.:
Environment: JDK1.5, JBoss 4.2.1 (with EJB3.0 embedded)
pps.:
Example code below:
| @Stateful
| public class MainProjectDTO implements MainProjectLocal, MainProjectRemote
| {
| public Project getProject()
| {
| // trivial example for my problem
| Query query1 = em.createQuery("FROM Project p WHERE p.id = 483");
| Project project = query1.getSingleResult();
|
| // the returned project is a proxy like Project_$$_javassist_16 but
| // should be an instance of RfAuthProject because it really is one.
|
|
| // here lies my problem
| // project with id=483 is definitly a RfAuthProject
| if (project instanceof Project) --> true
| if (project instanceof RfProject) --> false
| if (project instanceof RfAuthProject) --> false
|
| // following class cast fails
| RfAuthProject rfAuthProject = (RfAuthProject) project;
|
|
| return project;
| }
| }
|
Three entity beans in an inheritance hierarchy.
| @Entity
| @Inheritance(strategy = InheritanceType.JOINED)
| @Table(name = "project")
| public class Project
| {
| }
|
| @Entity
| @Table(name = "rf_project")
| @Inheritance(strategy = InheritanceType.JOINED)
| @PrimaryKeyJoinColumn(name = "id")
| public class RfProject extends Project
| {
| }
|
| @Entity
| @Table(name = "rf_auth_project")
| @Inheritance(strategy = InheritanceType.JOINED)
| @PrimaryKeyJoinColumn(name = "id")
| public class RfAuthProject extends RfProject
| {
| }
|
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http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4104908#4104908
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http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4104908
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