How to create a custom coder?

Question

I'm trying to create a custom coder AvroDeterministicCoder which is based on AvroCoder but returns true for isDeterministic.

In my example Dataflow I register this coder for all my PCollections. However, when I run my test it ends up throwing an exception: the key coder must be deterministic for grouping.

Using my debugger, I can tell that its using the coder AvroCoder.

In AvroDeterministicCoder do I need to add code to cause AvroDeterministicCoder to be deserialized as AvroDeterministicCoder and not as an AvroCoder?

Answer 1

It was a bug in my code; I needed to override the various of methods to return type AvroDeterministicCoder.

Here's the working code: AvroDeterministicCoder.