[AVRO-885] explicit schema verification

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Component/s: java
• Assignee: Unassigned
• Reporter: Yang Yang
• Created: 08/Sep/11 00:56
• Updated: 28/Oct/11 02:34

Description

when we declare some fields in a record, it's assumed to be mandatory unless we specify it with a union

{original_type, null}

.

this feature is actually very useful to me: I declare a schema, and if some new user creates a record, but fails to populate some mandatory field, I want some mechanism to throw an exception.

currently I get this feature "by accident": if the user misses some mandatory fields, when I send this record as a param to some RPC method, or when I serialize it through SpecificDatumWriter, Avro throws a NULLPointerException. I can catch this and let user know that it's due to lack of mandatory fields.

but instead of NPE, could we make Avro throw a more explicit exception, so it's more descriptive?

Thanks
Yang

On 09/07/2011 01:17 PM, Yang wrote:
> but instead of NPE, could we make Avro throw a more explicit exception,
> so it's more descriptive?

This is possible. It could be done back-compatibly by throwing a
subclass of NullPointerException, e.g., AvroNullValueException. The
logic in question is in GenericDatumWriter, where Avro builds an error
message indicating the path to the null in the data.

Please file an issue in Jira for this.

Doug