Hi, you are correct, the wrappers are lacking callbacks on CheckpointedFunction. This is not the intended design and should be added.
Best, Stefan > Am 05.01.2017 um 04:40 schrieb Eron Wright <ewri...@live.com>: > > Hello! > > The `CheckpointedFunction` interface was introduced to provide user functions > with a context for partitioned state storage. This works for user functions > that are provided directly to the operator (assuming it extends from > `AbstractUdfStreamOperator`). However, I see that some operators wrap the > user function in an internal function (e.g. `WrappingFunction`, > `InternalWindowFunction`). This defeats the callbacks on > `CheckpointedFunction` because those wrappers don’t implement > `CheckpointedFunction`. Is this by design or a bug? > > For example, the user function passed to `WindowedStream::apply` will get > callbacks for `RichFunction` but not for `CheckpointedFunction`. > > To fix it, the wrapper would assumedly implement `CheckpointedFunction` and > contain logic similar to that found in `AbstractUdfStreamOperator` (including > the handling of `ListCheckpointed`). > > Thanks > Eron
