I have looked at the Avro 1.6.0 code and am not sure how Avro distinguishes between field boundaries when reading null values.

The BinaryEncoder class (which is where I land when debugging my code) has an empty method for writeNull: how does the parser then distinguuish between adjacent nullable fields when reading that data?

Thanks in advance,

Andrew

The read part is empty as well, when the decoder is asked to read a
'null' type. For null carrying unions, I believe an index is written
out so if the index evals to a null, the same logic works yet again.

Does not matter if there are two nulls adjacent to one another,
therefore. How do you imagine this ends up being a problem? What
trouble are you running into?

On Mon, Jan 23, 2012 at 8:08 PM, Andrew Kenworthy
<[EMAIL PROTECTED]> wrote:
> I have looked at the Avro 1.6.0 code and am not sure how Avro distinguishes
> between field boundaries when reading null values.
>
> The BinaryEncoder class (which is where I land when debugging my code) has
> an empty method for writeNull: how does the parser then distinguuish between
> adjacent nullable fields when reading that data?
>
> Thanks in advance,
>
> Andrew

--
Harsh J
Customer Ops. Engineer, Cloudera

I don't have a specific use-class that is problematic, but was trying to understand how it all works internally. Following your comment about indexes I looked in GenericDatumWriter and sure enough the union is "tagged" so we know which part of the union was written:

case UNION:
        int index = data.resolveUnion(schema, datum);
        out.writeIndex(index);
        write(schema.getTypes().get(index), datum, out);
        break;

That's the bit I was missing! Thanks for the input.

Andrew

>________________________________
> From: Harsh J <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]; Andrew Kenworthy <[EMAIL PROTECTED]>
>Sent: Monday, January 23, 2012 4:04 PM
>Subject: Re: How does Avro mark (string) field delimition?
>
>The read part is empty as well, when the decoder is asked to read a
>'null' type. For null carrying unions, I believe an index is written
>out so if the index evals to a null, the same logic works yet again.
>
>Does not matter if there are two nulls adjacent to one another,
>therefore. How do you imagine this ends up being a problem? What
>trouble are you running into?
>
>On Mon, Jan 23, 2012 at 8:08 PM, Andrew Kenworthy
><[EMAIL PROTECTED]> wrote:
>> I have looked at the Avro 1.6.0 code and am not sure how Avro distinguishes
>> between field boundaries when reading null values.
>>
>> The BinaryEncoder class (which is where I land when debugging my code) has
>> an empty method for writeNull: how does the parser then distinguuish between
>> adjacent nullable fields when reading that data?
>>
>> Thanks in advance,
>>
>> Andrew
>
>
>
>--
>Harsh J
>Customer Ops. Engineer, Cloudera
>
>
>