Hi all,
I’m trying to model my domain to use GAE JDO. I have User and Event classes
(see below).
An Event is owned by a User and a User can participate in their and others
Events.
My issue is that I’m having trouble persisting the participate in another
User’s Event. I keep getting:
java.lang.IllegalArgumentException: can't operate on multiple entity groups
in a single transaction. found both Element {
type: "User"
id: 1
}
and Element {
type: "User"
id: 7
}
I see its because I’m updating multiple top level entities... but I’m not
sure how to update the entities separately given the own/participates
references... any suggestions appreciated!
@PersistenceCapable(detachable = "true")
public class User implements Serializable
{
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key id;
// owned one-to-many with event
@Persistent(mappedBy = "owner")
private List<Event> ownsEvents = new ArrayList<Event>();
// many to many
private Set<Key> participatesInEvents = new HashSet<Key>();
}
@PersistenceCapable(detachable = "true")
public class Event implements Serializable
{
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key id;
// owned one-to-many with user
private User owner;
// many to many with user
private Set<Key> participants = new HashSet<Key>();
}
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