Processing-Mode Equality

[Zhong Yu]

On Sun, Feb 9, 2014 at 6:42 AM, Doug Lea <dl at cs.oswego.edu> wrote:
> One slogan is "Data-centric, parallel-agnostic".
>
> On 02/08/2014 01:36 PM, Sam Pullara wrote:
>> That is one way to think about it and programming wise you would be correct.
>> However, if you run everything in parallel that can be you will likely be
>> disappointed in the performance.
>
> This of course assumes that people will continue to write programs in
> ways that present a high likelihood of disappointment. This is sure to
> sometimes happen: Classic object-oriented programmers will tend to use
> unpartitionable side-effecting methods, classic functional programmers
> will tend  to use hopelessly sequential data structures, and classic
> event-driven programmers will tend to use one-by-one vs bulk updates.
> Among those likely to cope best are database programmers, who are
> already comfortable with data-centric bulk updates.

Hi Doug, what do you mean by "updates" here?

Is the following example a sanctioned usage of Stream?

    widgetStream
        .filter( w->w.getColor()==red )
        .forEach( w->w.setColor(pink) );

>
>> A pretty special set of conditions need to
>> be present for it to make sense to run things in parallel.
>
> In some alternative universe, someone is now complaining that a
> pretty special set of conditions need to be present for it to make
> sense to run things sequentially even if eligible for parallelism:
> The combination of intrinsically sequential data structures,
> less than a few thousand elements, and trivially cheap per-element
> functions. If you designed programs so these cases rarely occurred,
> you wouldn't worry about occasional slowdowns when they do.
> But we cannot write such code for you. We cannot even tell you
> with certainty when you do/don't: Just trying to figure out the
> cost of per-element functions hits the Halting problem.
>
> We will see some bad reactions and experiences along the way
> as people decide how and when to use the Stream framework.
> And we will surely see people deciding to never use it because
> data-centric, parallel-agnostic programming clashes with their
> adopted programming style. Fine. Java (among other JVM languages)
> succeed because people with different religious views about
> programming can coexist.
>
> -Doug
>
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