Question

I’ve spent some time looking for some alternative to handle generic objects, I’ve seen questions similar to mine, but not as specific I suppose?
Protocol buffers has multiple scalar types that I can use, however they are mostly primitive.
I want my message to be flexible and be able to have a field that is a List of some sort.

Let’s say my .proto file looked like this:

   message SomeMessage
   {
      string datetime = 1;
      message inputData // This would be a list
      {
         repeated Object object = 1;
      }
      message Object 
      {
          ? // this need to be of a generic type - This is my question
          // My work around - Using extentions with some Object
          //List all primitive scalar types as optional and create an extension 100 to    max;
      }
      message someObject //some random entity - for example, employee/company etc.
      {  
          optional string name = 1; optional int32 id = 2;
      }
      extend Object 
      {
          optional someObject obj = 101;
      }
  } 

And this would be fine, and would work, and I’d have a List where Objects could be of any primitive type or could be List < someObject >.
However- The problem here, is that any time I needed to handle a new type of object, I’d need to edit my .proto file, recompile for C# and java (The languages I need it for)…

If protocol buffers is not able to handle generic object types, is there another alternative that can?
Any help on this matter is greatly appreciated.

Answer 1

As Marc Gravell stated above – Protocol Buffers do not handle generics or inheritance.