How to run code before JPA startup?

[bobthule]

I want a chance to run code before JPA starts up to have a chance to run SQL to modify the database.  The only way I can think of to try and accomplish this is to create a servlet with a low load-on-startup value.  Is that the best or only option?

[nickarls]

Isn't the boot order pretty much appserver-specific? What is it in JBoss? CDI/JSF/JPA?

[mwohlf]

take a look at liquibase if you want to do database upgrades/checks on startup

[bobthule]

Good point about the appserver-specific.  It will be CDI/JSF/JPA all deployed in a single war file.  It will be deployed on JBoss but in the future for other clients it may need to be deployed on Glassfish or Tomcat.

I looked at liquibase and they use a ServletListener to do the updates at startup, but I am unclear whether that doing it that way is guaranteed to run before JPA starts up.

It seems like JPA and/or Hibernate would have a hook to run code before it starts up but I couldn't find anything on that.  I also looked to see if Weld had a way, but I couldn't find it, either.

I would most prefer a solution with Weld.

[pmuir]

If you are on JBoss AS and just want to run SQL, Hibernate will execute the import.sql AFTER JPA gets set up.

You can't guarantee any ordering that I know of, and I don't know of a hook to do this.

[bobthule]

Thanks Pete,

Yeah I know about import.sql, but the goal is more to help ease customer installations by allowing database schema migrations to automatically run when the website starts up. 

I had an idea of creating my own PersistenceProvider and overriding the methods to do my upgrades and then passing off to the Hibernate PersistenceProvider.