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https://issues.apache.org/jira/browse/AVRO-1568?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14106366#comment-14106366
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Sachin Goyal commented on AVRO-1568:
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This works great for code which is directly under the developer's control.
But for cases where there are third party libraries having such constructs, it
becomes difficult to ask them to add such annotations in their code.
Maybe an API can be added to ReflectData as #addUnionSchema (Class baseClass,
Class derivedClasses[])
This will work the same as @Union but without the need to change third-party
code.
> Allow Java polymorphism in Avro
> -------------------------------
>
> Key: AVRO-1568
> URL: https://issues.apache.org/jira/browse/AVRO-1568
> Project: Avro
> Issue Type: New Feature
> 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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