I'm passed these problems now - a couple of things i learned when creating object and storing in data nucleus for later retrieval over an RPC call
- Most importantly, if you are returning a complex object (like one with a list of another type of object) you need to return a copy, not the object data nucleus returns - return persitenceManager.detachCopy (object) - the object returned by PM has all sorts of stuff in it that can't be serialized, the detached copy does not. Next, if your are creating an object with lists of other object that are not necessarily parent/child relationships or anything you want to persist, you need to decorate it with @NotPersistent because app engine will mark things as persistent for you even if you don't want it or mark it as persistent. See this note in the doc: Tip: JDO specifies that fields of certain types are persistent by default if neither the @Persistent nor @NotPersistent annotations are specified, and fields of all other types are not persistent by default. See the DataNucleus documentation for a complete description of this behavior. Because not all of the App Engine datastore core value types are persistent by default according to the JDO specification, we recommend explicitly annotating fields as @Persistent or @NotPersistent to make it clear. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-toolkit@googlegroups.com To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en -~----------~----~----~----~------~----~------~--~---
