topic JPA integration not working 100% for transient variables??? in Alfresco Archive

JPA integration not working 100% for transient variables???

tbee — Thu, 06 Sep 2012 08:52:51 GMT

I've setup JPA integration and initially it seems to work, but I find a deviation.My entity classes all extend an AbstractBean class where the code for a.o. property change events is present. This class also has the possibility to block (ignore) these events (this is required when setting up default

Re: JPA integration not working 100% for transient variables???

trademak — Thu, 06 Sep 2012 09:32:42 GMT

Hi,

Do you have async behavior in your process definition?
Can you create a unit test that shows this behavior?

Thanks,

Re: JPA integration not working 100% for transient variables???

tbee — Thu, 06 Sep 2012 10:02:07 GMT

I do not have an async process.

I'vecreated my own implementation, which generates a String from an entity (classname:id) and reloads the entity based on the information in the listener. This works without a problem. (It also has the advantage that, because I mix and match workflow and regular code, it makes sure only one EntityManager is used; no conflicts.)

A unit test, well it is happening as part of my own unit test, so I could strip that down… I'll give it a try.

Re: JPA integration not working 100% for transient variables???

tbee — Thu, 06 Sep 2012 10:45:14 GMT

Yeah. Now that I've stripped it down far enough, the problem is gone. So there is some kind of conflict between what I do in the frame of my application, and how Activiti restores the entity. So I can't give you a simple unit test that reproduces the problem.

What I do know is that:
- in the activiti implementation a final field ends up being null (that is very strange)
- using my simple implementation of encode-as-string and find-using-string in the same context works fine

My question would be: what magic are you guys doing to restore the entity? It seems the constructor is somehow by passed. (Note that I have 5 layer deep entity classes.) As said, this simple piece of code works fine:


 static public <T> T fromId(Object id)
 {
  try
  {
   // preconditions
   String lId = "" + id;
   if ("null".equals(lId)) return null;
   
   // split id
   int lIdx = lId.indexOf(":");
   String lClassname = lId.substring(0, lIdx);
   BigInteger lPK = new BigInteger(lId.substring(lIdx + 1));
   
   // get entity
   EntityManager lEntityManager = EntityManagerFinder.find();
   T lEntity = (T)lEntityManager.find(Class.forName(lClassname), lPK);
   return lEntity;
  }
  catch (ClassNotFoundException e) { throw new IllegalStateException(e); }
 }

I can offer you to take a remote-desktop peek in my development environment.

Re: JPA integration not working 100% for transient variables???

tbee — Thu, 06 Sep 2012 13:32:57 GMT

Hmmm. I've taken a peek at what is in the ACT_RU_VARIABLE table and I see that my approach stores a "nl.o837.frozn.bm.Application:74" text. However, Activiti seems to store a serializable. Do you actually serialize and store the whole entity? That should not be, the user manual says "When the variable is requested the next time, it will be loaded from the EntityManager based on the class and Id stored.".

Re: JPA integration not working 100% for transient variables???

tbee — Thu, 06 Sep 2012 14:58:29 GMT

It's the "transient" keyword; it tells Java's serializer to not serialize a field. And that is how you get a final field to become null…