On Thu, Jan 7, 2010 at 12:42 PM, Nigel Pickard <pickard.ni...@gmail.com>wrote:
> I read various messages on this subject in the message board, but > couldn't really find what I was looking for. Here is what I'd like to > do: > > 1. I have messages of type Animal, Vegetable and Mineral. > 2. I want to send these 3 dissimilar objects of Animal, Vegetable and > Mineral to a file or output stream using the writeDelimitedTo method > so I have an automatic delimiter. I do not know which order these > objects will be in. > > Since I don't know up front which type is coming first, from the > techniques section (http://code.google.com/apis/protocolbuffers/docs/ > techniques.html) I see I can use a wrapper message, and then > interrogate the wrapper message to determine the type. > > However, if we get many different potential types of messages, this > approach could get messy very quickly both from maintaining the proto > file (even with extensions) and interrogating the wrapper (e.g. > testing if the wrapper contains a certain type) . Are there any other > options I could use? Advantages/disadvantages? > Use the wrapper message technique combined with extensions: message Wrapper { extensions 100 to max; } // Can be in a different file. extend Wrapper { optional Animal animal_ext = 100; optional Vegetable vegetalbe_ext = 101; optional Mineral mineral_ext = 102; } > > One thought was to send a separate message object containing the type > information (could be as simple as a string such as a class name etc) > preceding each message, but I'm not sure that would work and it could > be very expensive. Has anyone else used anything different from the > way outlined in the techniques section? > > -- > 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<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.
