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From "Aleksey Shipilev" <aleksey.shipi...@gmail.com>
Subject Re: [classlib][luni][performance] IdentityHashMap implementation
Date Mon, 21 Apr 2008 12:50:19 GMT
Tim,

I'm thinking now about making IdentityHashMap to be similar with
HashMap. AFAIK, there are spec problems with overriding of existing
HashMap implementation on equality operation, so I want to go this
way:
 1. Copy-paste HashMap implementation to IdentityHashMap
 2. Change the equality checks and hashCode() calls to
IdentityHashMap-specific ones
 3. Merge the common code in AbstractMap to reduce code duplication.

Performance data can be available at (2), and no committing is
required on that step.

How this sounds?

Thanks,
Aleksey.

On Mon, Apr 21, 2008 at 4:45 PM, Tim Ellison <t.p.ellison@gmail.com> wrote:
> Alexey Varlamov wrote:
>
> > 2008/4/21, Aleksey Shipilev <aleksey.shipilev@gmail.com>:
> >
> > > Well, the implementation note is what confusing me.
> > > Can we ignore it and implement our own IdentityHashMap instead of
> > > open-addressed + linear probed + joint key/values array?
> > >
> >
> > I believe so (given that we respect other spec requirements). The
> > implementation note is a hint, not a part of actual spec IMO.
> >
>
>  Before committing to replace our current implementation, I'm interested to
> see some experiment and measurement of new ideas.  What could be done?
>
>  Regards,
>  Tim
>

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