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From "Mikhail Loenko" <mloe...@gmail.com>
Subject Re: Re: Re: [classlib] TwoKeyHashMap
Date Tue, 25 Jul 2006 07:34:52 GMT
Sorry, sent unfinished message

my version of priorities is:
1) Correct
2) Attractive to users
3) Easy to maintain

Thanks,
Mikhail


2006/7/25, Mikhail Loenko <mloenko@gmail.com>:
> 2006/7/25, Alex Blewitt <alex.blewitt@gmail.com>:
> > On 25/07/06, Mikhail Loenko <mloenko@gmail.com> wrote:
> > > In general before we get rid of that class or decide to keep it, I think
> > > we should work out an approach to performance optimizations.
> > >
> > > It's a rare case when perofmance might be significantly improved for free,
> > > a regular price is: additional complexity, more code, lack of readability,
> > > additional memory footprint etc.
> > >
> > > So let's discuss how we approach performance in general and that return to
> > > this specific class.
> >
> > Performance in general: premature optimisation is the root of all evil [Knuth]
> > http://mindprod.com/jgloss/knuth.html
> >
> > In this case, we've not only dupllicated logic from a HashMap, but at
> > the expense of a potential problem that we've not even measured. For
> > example, there is an assumption that the cost of creating (and
> > recycling) objects in a wrapper for an equivalent use of a Map is
> > something that's not even been measured, yet we have code that assumes
> > that that is a bottleneck.
> >
> > Is this code even on the critical path? That is, have we profiled this
> > code to know whether any access is actually directly responsible for
> > performance problems? If not, then it sounds like assumptions have
> > been made prior to writing this.
> >
> > So, we should strive to make code:
> >
> > 1) Correct
> > 2) Easy to understand and maintain
> > 3) Performant
> > 4) Optimised (for memory, speed)
> >
> > in that order. In this case, I'm not sure whether we've violated 2 in
> > preference for 4.
>
> Not sure I agree with your priorities
>
> Thanks,
> Mikhail
>
> >
> > Alex.
> >
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> >
>

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