On Thu, Apr 1, 2010 at 12:45 AM, John Patterson <[email protected]> wrote: > > All queries that are possible with the low-level datastore are possible with > Twig because there are low-level to type-safe "bridge" methods. So you can > simply do a typeless low-level ancestor query and then get Twig to convert > the resulting Entities into typesafe instances.
That's nonsense. This could only work if you've either encoded the full java package and classname into the Entity (a colossal mistake) or you've somehow registered a mapping (typically from Kind, but it could be any synthetic field) to the java class ahead of time. This means that Your framework can't perform magic. A truly polymorphic query (of which ancestor queries are one flavor) doesn't know the concrete type of the object until it's fetched from the datastore. If you don't understand this, you haven't thought about the problem enough. Jeff -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" 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/google-appengine-java?hl=en.
