Re: [ovirt-devel] hibernate's internal PersistentBag sent to FE

From: "Alexander Wels" <awels(a)redhat.com&gt; To: "Tomas Jelinek" <tjelinek(a)redhat.com&gt; Cc: "Liran Zelkha" <lzelkha(a)redhat.com&gt;, devel(a)ovirt.org Sent: Monday, June 1, 2015 4:19:47 PM Subject: Re: [ovirt-devel] hibernate's internal PersistentBag sent to FE On Monday, June 01, 2015 09:33:07 AM Tomas Jelinek wrote: > ----- Original Message ----- > > > From: "Alexander Wels" <awels(a)redhat.com&gt; > > To: devel(a)ovirt.org > > Cc: "Tomas Jelinek" <tjelinek(a)redhat.com&gt;, "Liran Zelkha" > > <lzelkha(a)redhat.com&gt; Sent: Monday, June 1, 2015 3:16:34 PM > > Subject: Re: [ovirt-devel] hibernate's internal PersistentBag sent to FE > > > > On Monday, June 01, 2015 09:08:50 AM Tomas Jelinek wrote: > > > Hey all, > > > > > > since the org.ovirt.engine.core.common.job.Job/Step... has been moved > > > to > > > use > > > the JPA we have a problem on frontend. The problem is that the > > > @OneToMany > > > annotations results in a List which is of type PersistentBag. When we > > > send > > > this to Frontend it fails during deserialization. It actually fails > > > quite > > > bad because the FE already has an ui-override of it which is not > > > correct > > > resulting in a ton of NPEs in development mode. > > > > > > So, there are 2 nasty fixes I have made where none of them should be > > > merged > > > but demonstrate the possibilities: 1: extend the FE to be able to work > > > with > > > the PersistentBag (https://gerrit.ovirt.org/#/c/41682/) not really good > > > solution since the PersistenBag is an internal Hibernate class which is > > > really not meant to be passed around > > > > > > 2: fix on the backend to not send the PersistentBag but an ArrayList. > > > This > > > is only a PoC fixed on a command we face the problem > > > (https://gerrit.ovirt.org/#/c/41797/) Obviously this is not going to > > > work > > > for other commands accessing the same Job nor for other entities. > > > > > > So, the first option is generic but very very bad. The second option > > > should > > > be used but not sure how to do this in a cheep way (e.g. without using > > > reflection to deep traverse everything sent back to frontend checking > > > if > > > it > > > does not have a PersistentBag in it. > > > > Tomas, > > > > Thanks, I was investigating the same issue, I noticed it last Friday just > > before leaving, so I was investigating the problem to see what was going > > on. You are right we should not be sending PersistentBag to the frontend > > at all. So how about we do a combination of [1] and [2], but instead of > > delegating in [1] we actually simple throw an exception stating don't > > sent PersistentBag to the front end. that way anyone inadvertently using > > it will be notified immediately (since their code won't work). > > Throwing the exception would help us in debugging but the main question is > how will we make it work? Since we are planning to move more and more to > JPA so we will face this issue more and more often. Solving it one by one > on backend in each command is not going to work. How about something like this [1]? It appears to use some aspects to translate the hibernate internal classes into normal java util classes. [1] https://code.google.com/p/dehibernator/

> > Alexander > > > > > Any better ideas? > > > Thanx, > > > Tomas > > > _______________________________________________ > > > Devel mailing list > > > Devel(a)ovirt.org > > > http://lists.ovirt.org/mailman/listinfo/devel _______________________________________________ Devel mailing list Devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/devel