[jboss-user] [JBoss Cache] New message: "Inconsistent behaviour when fetching cached subclass entities?"
User development,
A new message was posted in the thread "Inconsistent behaviour when fetching cached
subclass entities?":
http://community.jboss.org/message/527588#527588
Author : Jimmy Borg
Profile : http://community.jboss.org/people/jborg
Message:
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Hi all,
The use of jboss-cache as hibernate second-level cache is leading to inconsistent
behaviour when fetching cached subclass entities as opposed to fetching non-cached
subclass entities.
*Scenario*
Consider a simple scenario having a parent entity:
@Entity
@Table(name = "tt_test")
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
public abstract class ParentEntity implements Serializable {
private static final long serialVersionUID = 5751958972675892020L;
@Id
private String id;
protected ParentEntity() {
super();
}
public ParentEntity(String id) {
this.id = id;
}
public String getId() {
return id;
}
}
and two subclass entities extending the above entity:
@Entity
public final class Subclass1 extends ParentEntity {
private static final long serialVersionUID = -4329753920470094896L;
protected Subclass1() {
super();
}
public Subclass1(String id) {
super(id);
}
@Override
public String toString() {
return "Subclass1 [ID={" + getId() + "}, Class={" +
getClass() + "}]";
}
}
@Entity
public final class Subclass2 extends ParentEntity {
private static final long serialVersionUID = -6102575763486357670L;
/**
* Default constructor (required for hibernation reasons)
*/
protected Subclass2() {
super();
}
public Subclass2(String id) {
super(id);
}
@Override
public String toString() {
return "Subclass2 [ID={" + getId() + "}, Class={" +
getClass() + "}]";
}
}
After persisting an instance of Subclass1 using:
em.persist(new Subclass1("identifier1"));
Trying to fetch an instance of Subclass2 using:
em.find(Subclass2.class, "identifier1");
will result in a +null+ return if the entity is not cached. This is the expected, correct
behaviour.
However, when the entity with id +identifier1+ is cached, this will match and return an
instance (of Subclass1) if the entity is cached. This appears to be both inconsistent
behaviour, and a wrong result, as the entity with identifier +identifier1+ is of type
Subclass1 not SubClass2, as requested in the call to em.find().
*Environment*
jboss-cache 1.4.1.SP13
hibernate 3.2.5
jboss 4.2.2
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