What you want to do is create a Map<Descriptor, Message> which maps from descriptors to default instances of each of your generated classes. For example:
Map<Descriptor, Message> myMap = new ...; myMap.put(FooMessage.getDescriptor(), FooMessage.getDefaultInstance()); myMap.put(BarMessage.getDescriptor(), BarMessage.getDefaultInstance()); myMap.put(BazMessage.getDescriptor(), BazMessage.getDefaultInstance()); Now when you have a descriptor desc and you want to create a Builder for that type, you do: Message.Builder builder = myMap.get(desc).newBuilderForType(); When you call builder.build(), you will end up with a Message that can be down-cast to your generated type. DynamicMessage is meant to be used for types that aren't compiled in at all. So of course you can't cast from DynamicMessage to a generated class -- the generated classes are not subclasses of DynamicMessage. On Sat, Oct 31, 2009 at 7:57 AM, Martin Gilday <[email protected]>wrote: > > I am trying to write a service in Java which will convert back and > forth using protobufs. The docs say that this should be easy as > "Reflection is provided as part of the Message and Message.Builder > interfaces". However I cannot seem to find what this is referring to. > > I would like have a generic method which takes a Descriptor and a > stream which gives back an instance of message which I can later cast > to my desired type. I have tried DynamicMessage from = > DynamicMessage.parseFrom(descriptor, inputStream); but I get an > exception when I attempt to cast this as my generate proto class. > > Is there a solution to this? > > Thanks, > Martin. > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Protocol Buffers" 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/protobuf?hl=en -~----------~----~----~----~------~----~------~--~---
