Implement GenericObject - Allow GenericRecord to wrap any Java Object

[eolivelli]

Contents:

• introduce new high level interface GenericObject, that represents every logical value on the Pulsar topic
• allow AutoConsumeSchema to deal with every Schema type
• handle schema less topics with AutoConsumeSchema (return Bytes schema and byte[] payload)
• rename getNativeRecord to getNativeObject

How it works:

• in case of non struct schema, like for primitives and for KeyValue, wrap the result into a PrimitiveRecord class, that is an implementation of GenericRecord that wraps a Object and a SchemaType, it returns an empty list of "fields"

Intended audience:

• allow users to implement Sink, that is to write Sinks that work with every Schema type (the patch for Pulsar IO will follow up as a separate PR)

interface GenericObject {
      Object getNativeObject();
      SchemaType getSchemaType();
}
interface GenericRecord extends GenericObject

[eolivelli]

@jerrypeng @lhotari I have answered to your questions and renamed PrimitiveRecord to GenericObjectWrapper.

PTAL again

[codelipenghui]

LGTM

[eolivelli]

@sijie I have addresses your comments
PTAL again

[eolivelli]

@sijie CI passed.
can you please take a look again ?

[jerrypeng]

Is this interface suppose to be used as a schema type for producers or consumers, .e.g. Consumer ? If so, can you write some tests that has consumers / producers that uses this new type of Schema?

[jerrypeng]

Is there a reason why we need this interface as all. Shouldn't having these additional methods in GenericRecord suffice?

[eolivelli]

@jerrypeng
the idea is to let users user "GenericObject" instead of GenericRecord while dealing with "Any object", on the Consumer/Sink side, because GenericRecord for many users is related to a Struct type (like AVRO GenericRecord), and it carries "getFields()"

If so, can you write some tests that has consumers / producers that uses this new type of Schema?
I added tests about GenericObjectWrapper.

The main goal is to have Sink and having the ability to write Sinks that are not bound to a specific Schema at compile time.