[jpa-spec users] Re: Rollback and checking to see whether a class is an entity class

From: Linda DeMichiel <>
Date: Mon, 20 Jan 2014 10:57:45 -0800

Hi Laird,

On 1/20/14 10:14 AM, Laird Nelson wrote:
> Section 3.1.1 says:
> "Runtime exceptions thrown by the methods of the EntityManager interface
> other than the LockTimeoutException will cause the current transaction
> to be marked for rollback if the persistence context is joined to that
> transaction."
> Is this intended to cover the EntityManager#contains(Object) method?

Sure. It should be part of the application's logic to know what is an
entity or not.

> That method declares that it throws an IllegalStateException if the
> supplied Object is not an entity. That suggests to me that at runtime
> if I have an object in hand whose origin I'm not sure of then I can't
> simply blindly pass it to this contains() method, as that might result
> in transaction rollback. That seems kind of harsh to me.
> It would appear that the only safe way to check to see if an arbitrary
> object is both an entity and in the persistence context would be to
> first check to see if the object is in the metamodel's list of entities
> and then call EntityManager#contains(Object) passing it. This seems
> really cumbersome for a very common check.

What's the use case you are trying to address?



> So: should em.contains(arbitraryObjectFromSomewhere) cause the
> transaction to rollback if arbitraryObjectFromSomewhere is not in fact
> an entity? Is there another idiom for testing for entity-ness/hood that
> I'm missing?
> Best,
> Laird
> --