On Tue, Oct 6, 2009 at 11:04 AM, Rickard Öberg <[email protected]> wrote: > Hi, > > I tried using the Lifecycle interface to initialize Entity state, > specifically to set a "created on" Date property, but I realized that > Lifecycle is really of limited value in a system which uses EventSourcing, > as we do. > > The reason is that the entity itself is being created as a consequence of an > event, which can either happen at the point that the command to the domain > model is being processed, or much later during an event replay. In either > case the resulting domain model state much be exactly the same, and if > you're doing things in Lifecycle that is going to be tricky. > > In my case I was setting a Date property to "new Date()". During command > processing that would be fine, but during event replay that is entirely > wrong, since the date must be what it was when the event to create the > entity was generated. > > So, for this reason the Lifecycle interface, although potentially very > practical, is of limited use in an EventSourcing setup.
Yes, because you have your "lifecycle" baked into the Event themselves (projectCreated) and can therefor put such initialization in listeners/concerns of the event. That doesn't exclude practical usages elsewhere. Cheers -- Niclas Hedhman, Software Developer http://www.qi4j.org - New Energy for Java I live here; http://tinyurl.com/2qq9er I work here; http://tinyurl.com/2ymelc I relax here; http://tinyurl.com/2cgsug _______________________________________________ qi4j-dev mailing list [email protected] http://lists.ops4j.org/mailman/listinfo/qi4j-dev
