We do have a use case where we would need to veto the save, and we have a use case where we need to change (or add) values to an entity being saved. However, in the use case that I am dealing with now, we need to perform specific logic that notifies other entities that the value has changed.
On Apr 25, 9:06 am, Fabio Maulo <[email protected]> wrote: > The logic is for vetoing the save or to change values on the entity begin > saved ? > > > > On Mon, Apr 25, 2011 at 9:46 AM, j gwood <[email protected]> wrote: > > Here is the use case: > > > I have an entity that can get saved by being part of an object graph. > > When this entity is saved, I need to perform some logic based on > > whether or not the entity is new (being saved for the first time). > > > Using the example from the first post with the entities, Parent, > > Child, and Grandchild, I would perform the following: > > > - Select an existing Parent from the database that contains an > > existing Child and Grandchild. > > - Create a new Grandchild object and add it to the > > Parent.Child.Grandchild property. > > - Save the Parent entity. > > > Because I am saving the Parent entity, I really have no way of knowing > > if or when the new Grandchild entity will be saved/persisted. That is > > why we are subscribing to the NHibernate events - so we can be > > notified of when an entity is saved/persisted and perform appropriate > > validation or logic before the save occurs. > > > On Apr 22, 2:49 pm, Fabio Maulo <[email protected]> wrote: > > > perhaps you are looking to wrong events. > > > Which are exactly your needs ? (try to explain it from the usage point of > > > view and not what you think is the right behavior of NH). > > > > On Fri, Apr 22, 2011 at 3:20 PM, j gwood <[email protected]> > > wrote: > > > > I ran some additional tests: > > > > > 1) If I create and associate new Parent, Child, and Grandchild objects > > > > and call ISession.Persist(Parent), the PersistEventListener only gets > > > > fired for the Parent entity. The SaveOrUpdate events get fired for > > > > the Child and Grandchild entities. The PreInsert event gets fired for > > > > all three entities (Parent, Child, and Grandchild). > > > > > 2) Using the "Merge" test in the original post (i.e., selecting an > > > > existing Parent entity that contains existing Child and Grandchild > > > > entities; then adding a new/transient Grandchild entity), I called > > > > ISession.Persist instead of ISession.Merge. The PersistEventListener > > > > only gets fired for the Parent entity. The SaveOrUpdate event gets > > > > fired for the Child and Grandchild entities. The PreInsert event gets > > > > fired for the Grandchild entity. The PreUpdate event gets fired for > > > > the Child entity. > > > > > On Apr 22, 11:57 am, j gwood <[email protected]> wrote: > > > > > Our Repository exposes a Save(entity) method, which calls either > > > > > SaveOrUpdate (for transient entities) or Merge (for persisted > > > > > entities). We call Merge to handle detached entities. > > > > > > The Persist event listeners only get called from the > > > > > SessionImpl.Persist or SessionImpl.PersistOnFlush methods. Should we > > > > > substitute our SaveOrUpdate or Merge calls with Persist? > > > > > > Or, is there any documentation on when and how often the different > > > > > Event Listeners get called? > > > > > > Thanks so much for your help, > > > > > > Jean > > > > > > On Apr 22, 7:39 am, Fabio Maulo <[email protected]> wrote: > > > > > > > The Save/SaveOrUpdate is not so deterministic as you need. Probably > > > > > > you are looking for Persist. > > > > > > > -- > > > > > > Fabio Maulo > > > > > > > El 21/04/2011, a las 13:50, j gwood <[email protected]> > > > > escribió: > > > > > > > > I have the following hierarchy of entities: > > > > > > > > Parent > > > > > > > Child > > > > > > > Grandchild > > > > > > > > The Parent entity contains a property for the Child entity. The > > > > Child > > > > > > > entity contains a property for the Grandchild entity. Each > > > > > > > relationship is a one-to-one relationship that is mapped in > > > > > > > the .hbm.xml file using one-to-many in order to use the cascade > > > > > > > option, all-delete-orphan (see NH-1262 > > > >http://216.121.112.228/browse/NH-1262). > > > > > > > > I am using both a MergeEventListener and a > > SaveOrUpdateEventListener > > > > > > > to get notified when the Grandchild entity is saved so I can > > perform > > > > > > > logic in case the Grandchild is saved due to a cascade from > > Parent or > > > > > > > Child. I check the Version property of the Grandchild entity to > > > > > > > perform certain logic based on whether or not the entity is > > transient > > > > > > > or persisted. > > > > > > > > In the following scenario, the SaveOrUpdate (or Merge) events are > > not > > > > > > > being fired for the Grandchild entity until after the entity has > > been > > > > > > > "persisted" or had its Version number changed from 0 to 1: > > > > > > > > - Select an existing Parent from the database that contains a > > Child > > > > > > > and Grandchild. > > > > > > > - Create a new/transient Grandchild object and add it to the > > > > > > > Parent.Child.Grandchild property. > > > > > > > - Merge (or SaveOrUpdate) the Parent entity. > > > > > > > > using (ISession session = this.OpenSession()) > > > > > > > { > > > > > > > using (ITransaction transaction = > > session.BeginTransaction()) > > > > > > > { > > > > > > > Parent startingParent = > > > > > > > session.Get<Parent>(this.ExpectedParentId); > > > > > > > > Grandchild closedGrandchild = new Grandchild > > {StatusValue > > > > > > > = "Closed"}; > > > > > > > startingParent.Child.Grandchild = closedGrandchild; > > > > > > > > Parent actualParent = > > > > > > > (Parent)session.Merge(startingParent); > > > > > > > > transaction.Commit(); > > > > > > > } > > > > > > > } > > > > > > > > When session.Merge or session.SaveOrUpdate are called, the > > > > > > > MergeEventListener (or SaveOrUpdateEventListener) for the Parent > > > > > > > entity gets fired, but no other events are fired at this time. > > > > > > > However, when the SaveOrUpdateEventListener is finally fired for > > the > > > > > > > Child and Grandchild entities during transaction.Commit(), the > > > > > > > Grandchild.Version property is already set to 1 (i.e., > > persisted). > > > > > > > The Version was updated during the Merge of the Parent entity > > when > > > > the > > > > > > > merge/save was cascaded down to the Grandchild entity: > > > > > > > > [Class=NHibernate.Engine.CascadingAction]: cascading to merge: > > > > > > > NHibernate.Test.NHSpecificTest.NHEvents470.Grandchild > > > > > > > [Class=NHibernate.Engine.VersionValue]: unsaved-value: 0 > > > > > > > [Class=NHibernate.Event.Default.AbstractSaveEventListener]: > > > > transient > > > > > > > instance of: > > NHibernate.Test.NHSpecificTest.NHEvents470.Grandchild > > > > > > > [Class=NHibernate.Event.Default.DefaultMergeEventListener]: > > merging > > > > > > > transient instance > > > > > > > [Class=NHibernate.Event.Default.AbstractSaveEventListener]: > > > > generated > > > > > > > identifier: beb25e35-45cd-4093-b88e-9b166c5ca7f0, using strategy: > > > > > > > NHibernate.Id.Assigned > > > > > > > [Class=NHibernate.Event.Default.AbstractSaveEventListener]: > > saving > > > [NHibernate.Test.NHSpecificTest.NHEvents470.Grandchild#beb25e35-45cd-4093- > > > > > > > b88e-9b166c5ca7f0] > > > > > > > [Class=NHibernate.Engine.VersionValue]: unsaved-value: 0 > > > > > > > [Class=NHibernate.Engine.Versioning]: Seeding: 1 > > > > > > > > The behavior is similar for SaveOrUpdate as the > > Grandchild.Version > > > > > > > property gets incremented to 1 before the > > SaveOrUpdateEventListener > > > > is > > > > > > > called. > > > > > > > > Is this the expected behavior of NHibernate? I would've expected > > the > > > > > > > MergeEventListener or SaveOrUpdateEventListener to get called > > when > > > > > > > each "child" entity is being saved on the cascades at the same > > time > > > > as > > > > > > > the "parent" object is being saved instead of seeing the events > > fired > > > > > > > for the "child" entities during transaction.Commit(). > > > > > > > > -- > > > > > > > You received this message because you are subscribed to the > > Google > > > > Groups "nhusers" group. > > > > > > > To post to this group, send email to [email protected]. > > > > > > > To unsubscribe from this group, send email to > > > > [email protected]. > > > > > > > For more options, visit this group athttp:// > > > > groups.google.com/group/nhusers?hl=en. > > > > > -- > > > > You received this message because you are subscribed to the Google > > Groups > > > > "nhusers" group. > > > > To post to this group, send email to [email protected]. > > > > To unsubscribe from this group, send email to > > > > [email protected]. > > > > For more options, visit this group at > > > >http://groups.google.com/group/nhusers?hl=en. > > > > -- > > > Fabio Maulo > > > -- > > You received this message because you are subscribed to the Google Groups > > "nhusers" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group at > >http://groups.google.com/group/nhusers?hl=en. > > -- > Fabio Maulo -- You received this message because you are subscribed to the Google Groups "nhusers" group. 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