[infinispan-dev] Protostream marshaller support for optional fields

[Adrian Nistor]

Hi Galder,

There's nothing special about optional fields. It is the required fields 
that are special: they do not allow null (in the read/write methods).

If a field is optional in your protobuf schema you can write a null 
value and protostream will happily interpret that as a missing value and 
will not write any tag in the output protobuf stream.
Reading a missing value will return a null. The required/optional status 
of a field is checked against the schema at runtime, so you cannot cheat :).

None of the above holds true for a required field. Writes will only 
accept non-nulls (an exception is thrown immediately). Reads will always 
return a non-null value, so you can safely use a 
primitive-type-returning read method. If the input stream does not 
contain a required field (probably because the encoder that produced it 
was violating the schema) an exception is thrown.

Adrian

On 10/23/2017 06:51 PM, Galder Zamarreño wrote:
> Hey Adrian,
>
> Quick q: how is a protostream marshaller supposed to deal with optional fields?
>
> I don't see any writer methods that deal with those... is it up to the user to put something on the wire to decide at read time whether the optional field follows or not?
>
> Cheers,
> --
> Galder Zamarreño
> Infinispan, Red Hat
>