Because @PostUpdate can only be apply in zanata-model. I can't reference other classes in zanata-war. 
EntityListener registered in orm.xml works. But it only gives you current entity in the callback. I also need to know its previous state such as previous content state and previous version number in order to prepare for an undo. 

----- Original Message -----

> From: "Carlos Munoz" <notifications@github.com>
> To: "zanata/zanata-server" <zanata-server@noreply.github.com>
> Cc: "Patrick Huang" <pahuang@redhat.com>
> Sent: Friday, January 31, 2014 4:08:16 PM
> Subject: Re: [zanata-server] Unify broadcast transunit updated event (#347)

> In
> zanata-war/src/main/java/org/zanata/webtrans/server/TranslationUpdateListener.java:
> > +import lombok.EqualsAndHashCode;
> > +import lombok.RequiredArgsConstructor;
> > +import lombok.extern.slf4j.Slf4j;
> > +
> > +/**
> > + * Entity event listener for HTextFlowTarget.
> > + *
> > + * @author Patrick Huang <a
> > + *         href="mailto:pahuang@redhat.com">pahuang@redhat.com</a>
> > + */
> > +@Name("translationUpdateListener")
> > +@Scope(ScopeType.APPLICATION)
> > +@AutoCreate
> > +@Slf4j
> > +public class TranslationUpdateListener implements PostUpdateEventListener,
> > +        PostInsertEventListener {

> Couldn't we have done all this with Entity listeners, forgoing the need for
> an Integrator?
> What's the difference between these listeners and plain old JPA entity
> listeners annotated with @PostUpdate @PostPersist?

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