I am trying to remove an object from the datastore without and I want
to know if my approach can be made to work with transactions.
I have a collection of entities that all participate in owned
relationships. However, one entity has an unowned collection of keys
that refer to another entity.
Here is the basic structure:
EmailList owns DirectContacts
EmailList owns IndirectContactLists
IndirectContactList owns IndirectContacts
DirectContact has an unowned collection of keys of IndirectContacts
(because an entity can only have one parent)
If I grab an IndirectContactList from the datastore and get the owning
EmailList and then proceed to traverse through the EmailList's
DirectContacts and remove the key of the IndirectContacts can I do
this within the context of a transaction? Here is a code snippet
without transactions:
//used to interact with the datastore
//create the entity manager
EntityManager em = EMF.get().createEntityManager();
try
{
//get the indirect contact list
IndirectContactList icl = em.find(IndirectContactList.class,
keyOfIndirectContactList);
if(icl != null)
{
//get the email list from the icl
EmailList eml = icl.getOwningEmailList();
//get the direct contacts for the email list
for(DirectContactEmail dce : eml.getDirectContactEmails())
{
//is this transaction safe??? if not, would grabbing
the email
//list first make it safe?
//now remove the reference to the icl
dce.getKeysOfIndirectContactEmails().remove(keyOfIndirectContactList);
}
//remove the indirect contact list and all the owned indirect
contact emails
em.remove(icl);
}
else
{
throw new IndirectContactListDoesNotExistException();
}
}
finally
{
em.close();
}
Can I add transaction code and expect that removing the unowned keys
will succeed/fail with the removal of the indirect contact list?
--
You received this message because you are subscribed to the Google Groups
"Google App Engine for Java" group.
To post to this group, send email to google-appengine-j...@googlegroups.com.
To unsubscribe from this group, send email to
google-appengine-java+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/google-appengine-java?hl=en.
