[AVRO-2357] (ReflectData) Support for generic types in protocol definitions

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 1.9.0
• Component/s: java
• Assignee: Ivan Greene
• Reporter: Ivan Greene
• Created: 26/Mar/19 00:53
• Updated: 07/Feb/20 10:08
• Resolved: 01/Apr/19 20:06

Description

For a Java interface extending another interface with type parameters, we may resolve actual type parameters and build the protocol definition based upon those.

For example, let's say we have a generic protocol defined by a Java interface:

public interface CrudProto<T, I> {
  void persist(T record);

  T fetchById(I id);
}

It would be natural to define a set of interfaces that extend this, such as:

public interface FooBarRecordProto extends CrudProto<FooBarRecord, String> {}

public interface OtherRecordProto extends CrudProto<OtherRecord, Long> {}

Calling ReflectData.get().getProtocol(FooBarRecordProto.class) should be able to resolve that this protocol deals in FooBarRecords and Strings, and build a protocol accordingly.

Currently, this call will produce an exception stating that a schema for 'T' cannot be resolved.

Issue Links

• links to: GitHub Pull Request #490