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https://issues.apache.org/jira/browse/AVRO-1568?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14500486#comment-14500486
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Ryan Blue commented on AVRO-1568:
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bq. Do we expect avro-serializiable classes to have these APIs?
Yes and no. I would expect the API to have enough information to be able to
reconstruct the object, but I don't think it would necessarily have such a nice
API to provide a serialized version of itself. I think the more common case
would be like the following, where you have a factory method (or constructor)
and accessors for the data:
{code:java}
interface Point:
cartesianPoint(float x, float y)
polarPoint(float r, float theta)
float getX()
float getY()
{code}
Here we don't know anything about the internals of the concrete Point
implementation, but can construct perfectly reasonable points.
> Allow Java polymorphism in Avro for third-party code
> ----------------------------------------------------
>
> Key: AVRO-1568
> URL: https://issues.apache.org/jira/browse/AVRO-1568
> Project: Avro
> Issue Type: Improvement
> Affects Versions: 1.7.6
> Reporter: Sachin Goyal
>
> A large number of Java designs interacting with databases with
> Hibernate/Couchbase (perhaps, even otherwise) have Java polymorphism of the
> form:
> {code:java}
> class Base
> {
> Integer a = 5;
> }
> class Derived extends Base
> {
> String b = "Foo";
> }
> class PolymorphicDO
> {
> Base b = new Derived();
> }
> {code}
> Jackson handles this kind of field by using annotations such as:
> {code}
> @JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include =
> JsonTypeInfo.As.PROPERTY, property = "@class”)
> {code}
> If such a thing can be added to Avro, all those Java designs could become
> immediately usable with Avro. They would also become Hadoop compatible due to
> AvroSerde.
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