Hi,

I'd like to subclass the avro-generated classes.

Is it possible to tell avro to deserialize using a custom builder that
instantiates my subclasses?

There are some hints in the source code that this might be possible, but
what I'd really like is a small, working example...

Thanks!

On 05/17/2012 11:54 AM, Joel VanderWerf wrote:
>
> I'd like to subclass the avro-generated classes.
>
> Is it possible to tell avro to deserialize using a custom builder that
> instantiates my subclasses?
>
> There are some hints in the source code that this might be possible, but
> what I'd really like is a small, working example...

This may be what I'm looking for:

org.apache.avro.specific.SpecificData

The getClass() method perhaps can be overridden to map incoming record
class names to java classes. Not sure if this is the right way to do it
though. There's also a getClassName() which might be a better method to
override.

Any thoughts?

What we are trying to do is emulate JAXB's ObjectFactory
functionality[1], which lets you specify which subclasses of the
generated classes are used for deserialization.

-----
[1] http://jaxb.java.net/guide/Adding_behaviors.html

On 06/05/2012 05:01 PM, Joel VanderWerf wrote:
> This may be what I'm looking for:
>
> org.apache.avro.specific.SpecificData
>
> The getClass() method perhaps can be overridden to map incoming record
> class names to java classes. Not sure if this is the right way to do it
> though. There's also a getClassName() which might be a better method to
> override.
>
> Any thoughts?

Overriding one of the two of these sounds like the right thing.
getClass() is implemented in terms of getClassName(), so if getClass()
otherwise does what you want and supplying a different class name is
sufficient then just override getClassName().  If you need to instead
override getClass() then you'll probably want to invoke super.getClass()
for non-record schemas.

I hope this helps.

Doug