Primitive streams and optional

[Doug Lea]

On 12/05/12 07:42, Remi Forax wrote:
> This experience among others led to the non-nulls policy in j.u.c.
>
> If we can go back in time and disallow null for all collections, we will live in
> a better world, but that not the case.

If we could go back in time and disallow null for all streams, we will
live in a better world. Oh, wait! We don't have to go back in time!
We can just make a better world!


> I'm pretty sure that because j.u.c collections use null to tag entry that should
> be removed and because the VM aggressively optimizes value that was never null
> before, code that triggers de-optimization the first time you remove an element
> from a concurrent collection should exist.

I'm pretty sure that all such cases are OK because they trigger
different branches that would somehow need encoding anyway.
So branching on null vs branching on something else is a wash.
(Although there might be a case here and there where different
encodings might win because they currently disable triggerings
of agressive-null mechanics that would otherwise be enabled
along branches.


-Doug