Re: [plugin-ins] AbstractGroupScan.getScanStats()

[Daniel Barclay <db...@maprtech.com>]

I wrote:
> Method org.apache.drill.exec.physical.base.AbstractGroupScan.getScanStats()
> has a body that throws a "This must be implemented" exception.
>
> Why isn't getScanStats() simply an abstract method?
>
> (Is there any case in which a subclass doesn't need to implement the
> method (i.e., where that method won't ever be called for that subclass)?)
> ...
EasyGroupScan does not override AbstractGroupScan.getScanStats(). Is it supposed to?

That is, is it the case that the intended contract is that each (concrete) subclass of AbstractGroupScan provides its own implementation of (overrides) that method, and that EasyGroupScan isn't fulfilling that contract, but no currently existing code happens to use that part of the contract, so it's a bug that hasn't been detected yet?

Or is it the case that the intended contract is that a subclass need to provide an implementation of that method only under some conditions?

If it's the later, what are the conditions?


Thanks,
Daniel

-- 
Daniel Barclay
MapR Technologies