Thanks It looks like there is no elegant way to solve my issue. In short, I have a transport implementation to use with PB RPC service. Service definitions are built-in and I need to convert byte array to Message inside my transport. I know what service transport handles and I have method name. ServiceDescriptor has descriptors of all types I possibly need, but unfortunately I looks like there is no way to construct message from byte array having MessageDescriptor (which I can get from ServiceDescriptor).
On Feb 23, 7:28 pm, Kenton Varda <ken...@google.com> wrote: > (But to answer your question: Compiled-in types are almost always faster > than DynamicMessage.) > > > > On Tue, Feb 23, 2010 at 4:27 PM, Kenton Varda <ken...@google.com> wrote: > > I'm not sure how your approach works, but since it looks like you're using > > Java reflection, my guess is that it will only work with compiled-in > > services. If your code is a library, this will prevent users of that > > library from using dynamic types, which is unfortunate. If the users > > provide a default instance, then they can choose to provide either a > > compiled-in type or a dynamic type. > > > On Tue, Feb 23, 2010 at 1:55 PM, ph <pkirsa...@gmail.com> wrote: > > >> Thanks Kenton, > > >> I was using getRequestPrototype, but I need an actual instance of > >> Service to call that method that created additional extra dependency > >> in my code that why I started to look for alternatives. I know my > >> method name and currently I'm just parsing response (byte array) this > >> way (in Scala): > >> Class.forName ( String.format ( classNameFormat, methodName ) ) > >> .getDeclaredMethod ( "parseFrom", Array ( msg.getClass ) : _* ) > >> .invoke ( null, Array ( msg ) : _* ).asInstanceOf > >> [ com.google.protobuf.GeneratedMessage ] > >> This works fine. I will try to use a Default Message or > >> DynamicMessage, thanks for suggestion. From the top of your head, do > >> you think DynamicMessage will be faster or slower than my approach? > > >> On Feb 22, 6:10 pm, Kenton Varda <ken...@google.com> wrote: > >> > Right, Descriptor.toProto() returns a DescriptorProto, which is itself a > >> > protobuf type. So, calling newBuilderForType() on that is going to > >> return a > >> > builder for DescriptorProto, not a builder for the type described. > > >> > What you want is com.google.protobuf.DynamicMessage. > > >> > Note that DynamicMessage is slower than the message classes produced by > >> > protoc. So if the type in question is actually compiled in to your app, > >> you > >> > should use it instead. Typically what you'd do is pass around the > >> type's > >> > default instance (MyMessageType.getDefaultInstance()) instead of passing > >> > around the descriptor. > > >> > Note that the Service interface also provides a method > >> > getRequestPrototype(MethodDescriptor) which returns the default instance > >> for > >> > the type, on which you can then call newBuilderForType(). > > >> > On Sat, Feb 20, 2010 at 12:54 PM, ph <pkirsa...@gmail.com> wrote: > >> > > I'm trying to build service return message using > >> > > Descriptors.ServiceDescriptor. > >> > > This does not work: > >> > > serviceDescriptor.findMethodByName > >> > > ( methodName ).getOutputType.toProto.newBuilderForType.mergeFrom > >> > > ( msg ).build > >> > > "msg" is byte array > >> > > It builds DesscriptorProtos.DescriptorProto instead of Message. > > >> > > Is there a way to build message from byte array using method > >> > > descriptor? > > >> > > -- > >> > > You received this message because you are subscribed to the Google > >> Groups > >> > > "Protocol Buffers" group.>> > > To post to this group, send email > >> > > toproto...@googlegroups.com. > >> > > To unsubscribe from this group, send email to>> > > >> > > >protobuf+unsubscr...@googlegroups.com<protobuf%2bunsubscr...@googlegroups.com> > >> <protobuf%2bunsubscr...@googlegroups.c om> > >> > > . > >> > > For more options, visit this group at > >> > >http://groups.google.com/group/protobuf?hl=en. > > >> -- > >> You received this message because you are subscribed to the Google Groups > >> "Protocol Buffers" group.>> To post to this group, send email > >> toproto...@googlegroups.com. > >> To unsubscribe from this group, send email > >> to>>protobuf+unsubscr...@googlegroups.com<protobuf%2bunsubscr...@googlegroups.com> > >> . > >> For more options, visit this group at > >>http://groups.google.com/group/protobuf?hl=en. -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to proto...@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
