Nulls

[Bob Lee]

3.

Bob

On Wed, Sep 26, 2012 at 5:13 PM, Sam Pullara <sam at sampullara.com> wrote:

> I choose 3. Easy to filter them out if you like 2 or fail if you like
> 1. 4 is just weird to me.
>
> Sam
>
> On Wed, Sep 26, 2012 at 1:00 PM, Brian Goetz <brian.goetz at oracle.com>
> wrote:
> > Trying again to categorize the choices and identify pros/cons...
> >
> > Seems like there are four buckets here:
> >
> > 1.  Ban nulls.  This means that feeding nulls into a Stream MUST produce
> an
> > NPE.
> >
> > 2.  Ignore nulls.
> >
> > 3.  Tolerate nulls.  Streams API takes no position on nulls, but may well
> > pass elements to less tolerant destinations (e.g., user-provided lambdas,
> > user-provided collections, Optional constructor.)  Nulls may cause NPEs
> in
> > these cases.
> >
> > 4.  Embrace nulls.  Ensure that every operation can deal with nulls in a
> > well-defined manner.  (This entails, for example, either dropping the
> > Optional-bearing methods or making present Optional deal with null.)
> >
> >
> > I think its safe to say that for each of these, there is some subset of
> us
> > who finds it undesirable.
> >
> > Doug proposed (2) and (4).  I proposed (3).  Nearly everyone has some
> > sympathy for (1) but no one really wants to be that intolerant.
> >
> >
> > Attempted summary of pros/cons:
> >
> > 1 PRO: Predictable, simple
> > 1 CON: Might be overly harsh, interferes with when user might actually
> want
> > to see nulls and can deal accordingly
> >
> > 2 PRO: Simple
> > 2 CON: size() lies, interferes with optimizations, interferes with when
> user
> > might actually want to see nulls and can deal accordingly
> >
> > 3 PRO: Minimizes distortion on API, implementation in the null-free case
> > 3 CON: more complex reasoning about what might happen, op behavior may
> > change subtly over time as implementation changes
> >
> > 4 PRO: Predictable
> > 4 CON: sacrifices functionality/safety for sake of a corner case
> >
> >
>