[jboss-as7-dev] Setting JPA ClassTranformer and how can a service be started before any DUPs start scanning deployment classes?

[Scott Marlow]

I need to start the JPA persistence unit service 
(javax.persistence.EntityManagerFactory), before the deployments classes 
have been read.  Currently, POST_MODULE_INJECTION_ANNOTATION and other 
DUPs can read application classes before the persistence unit service is 
started.

I tried changing the JPA related DUPs to start as early as possible but 
that doesn't help since the JPA persistence unit service doesn't 
actually start until the INSTALL phase (well after the 
POST_MODULE_INJECTION_ANNOTATION has already read application classes).

If we were to create the javax.persistence.EntityManagerFactory during 
an early PHASE (probably in a "first time access" phase after the module 
is defined), we would also need the datasource to be available early (to 
handle certain cases that require it (e.g. creating database tables or 
checking JDBC DatabaseMetaData.)

Is there a way to get early (equivalent to PHASE.POST_MODULE time) 
access to a datasource? 
https://github.com/scottmarlow/jboss-as/tree/AS7-4996_class_transformer_part2 
contains some hacks that I started and the current JPA datasource access 
code is at 
https://github.com/scottmarlow/jboss-as/blob/AS7-4996_class_transformer_part2/jpa/core/src/main/java/org/jboss/as/jpa/processor/PersistenceUnitServiceHandler.java#L318

AS7-4996 is the jira for this change and contains an IRC transcript from 
a conversation last fall about getting JPA class transformers to work. 
The changes that we made last fall, worked for the simple test case but 
not all applications.

Scott