I am having the same problem as brendan. I thing that everyone trying to get beyond hello-world gwt + gae/j also hit this wall. Is there a "best workaround" for this? must i use gilead? I really would like to see this on google tutorials, like the other frameworks mentioned by Philip, so that learning gwt+gae/j gets less fustrating.
On Apr 27, 9:09 pm, brendan <brendanpdohe...@gmail.com> wrote: > It's sounds like Philip is describing me. I've said "GWT and GAE/J > looks impressive, I want to put them together and make an nice app". > > In my test application i'm creating, I want to have a grid of > customers that has new, edit and delete buttons. > > A customer has a name and an email. > > I've created a customer class on the server that has name and email as > strings, with getters/setters. > > I've created an RPC service that has the following methods: > List<Customer> list() > Customer create(Customer customer) > void update(Customer customer) > void delete(Customer customer) > > Initially list was returning a hard coded list, and I put some > breakpoints in the other methods to see that objects were successfully > being passed over RPC. > > Everything seemed to work and I was thinking this GWT+GAE/J stuff is > pretty awesome. > > Then I tried to add persistence, and things stopped working. > I added the @PersistenceCapable annotation to my customer class, along > with an extra id attribute that had an @PrimaryKey annotation. > > When I try to return the results of a query.execute() (casted to > List<Customer>) I got the following error. > > SEVERE: [1240842247754000] javax.servlet.ServletContext log: Exception > while dispatching incoming RPC call > com.google.gwt.user.client.rpc.SerializationException: Type > 'org.datanucleus.store.appengine.query.StreamingQueryResult' was not > included in the set of types which can be serialized by this > SerializationPolicy or its Class object could not be loaded. For > security purposes, this type will not be serialized. > > I fiddled around a bit more and found that if I copied Customers out > of the list returned by query.execute to a new list (using the > detachCopy method) and returned that, I could populate my grid. > > However when it comes time to saving/deleting Customers, I tried > "reattaching" by calling makePersistant, it wouldn't work I got more > errors. > > Pretty much, I'm a javascript/c++/c#.net programmer coming to GWT and > GAE/J, I want to put them together and make an nice app. > > If I want things to work right now, what is best practice for having > persistent objects on the server, and sending the data back and forth > from the server to the client. > > Brendan > > On Apr 15, 6:40 pm, philip <philip14...@gmail.com> wrote: > > > Thats fine your debating how best to do it for the longer term, and > > thats great for the longer term. How about now today? how best can I > > do it now? > > > For the shorter term I am sure there is a bunch of people who look at > > this and think, I've got GWT and Google App Engine, I want to put them > > together and make an nice app, then they come across these > > discussions. Alternatively, they try to serialize the JDO classes and > > find they have problems. Either way, they hit the ugly wall. > > They probably wonder why GWT and App Engine are not such good friends > > such it would make a great programming platform and boost GWT. > > > ... > > > Thanks, Philip --~--~---------~--~----~------------~-------~--~----~ http://groups.google.com/group/Google-Web-Toolkit-Contributors -~----------~----~----~----~------~----~------~--~---
