Hi Juanjo, > the data objects will reside at the http session, and will be used directly > by the vaadin widgets, does this kind of cayenne data objects "use" could > arrive with attaching/detaching problems?
Shouldn't be a problem. You can store Cayenne objects in a session. The simplest way to avoid attach/detach issues is to have a session-scoped ObjectContext. Then it is serialized/deserialized together with the objects in case the session is saved to disk, or replicated across the cluster. > Also, is there a way to add metadata info in cayenne metamodel? I would like > to add constraints / validations to generated classes, so they can be used to > define searching criterias on indexed attributes (something like > active-records class filters, but only on indexed properties) and generate > model validations on properties so they can be used at UI fields directly, > facilitating the app development. You can add extra info using callbacks or lifecycle listeners. Any extra properties can be defined either manually in generated subclasses, or even stored in the base CayenneDataObject (with 'readProperty' / 'writeProperty' methods, and custom property names). > Finally, I'm looking for a multitenant implementation to use, and I believe > that the solution pointed at > http://blog.jerodsanto.net/2011/07/building-multi-tenant-rails-apps-with-postgresql-schemas/ > could be also used with cayenne; is there any constraint I should look for? Cayenne is certainly friendly to various multi-tenancy approaches. In 3.1 API terms, you might assign a separate instance of ServerRuntime to each tenant, and use that to create ObjectContexts for its users. You may start all runtimes from the same basic configuration, and "namespace" them using tenant-unique DB URL. Or you may use a single DataSource, and after a runtime is loaded, scan through all its DbEntities and assign a tenant "schema" to them. Feel free to ask about further details. Andrus On Aug 26, 2012, at 5:15 PM, Juan J. Gil wrote: > Hello, I'm thinking to use cayenne in conjunction with vaadin > (http://vaadin.com). > > I'm trying to use some kind of tight integration between both frameworks > (defining cayenne generated classes which are vaadin data models > implementations). > That way I could define forms directly on data objects, querying & mutating > its state directly from vaadin widgets. > As vaadin is an stateful web framework, should I have to expect for some kind > of problem with data objects between requests? I mean, the data objects will > reside at the http session, and will be used directly by the vaadin widgets, > does this kind of cayenne data objects "use" could arrive with > attaching/detaching problems? > > Also, is there a way to add metadata info in cayenne metamodel? I would like > to add constraints / validations to generated classes, so they can be used to > define searching criterias on indexed attributes (something like > active-records class filters, but only on indexed properties) and generate > model validations on properties so they can be used at UI fields directly, > facilitating the app development. > > Finally, I'm looking for a multitenant implementation to use, and I believe > that the solution pointed at > http://blog.jerodsanto.net/2011/07/building-multi-tenant-rails-apps-with-postgresql-schemas/ > could be also used with cayenne; is there any constraint I should look for? > > Best regards > Juanjo > > ps: pardon my really poor English! :P > >
