[announce] InhiBeans: mitigate redundant recalculations

[Tomas Mikula]

On Sun, Dec 15, 2013 at 6:39 PM, Scott Palmer <swpalmer at gmail.com> wrote:
> Interesting idea.
>
> There is a case I have been curious about and wonder what the best practices
> are for it.  Suppose you have a case when you are changing multiple
> different properties that will be used in a single calculation.  You want to
> deal with a single change to all of them in one go.  E.g. imagine you have
> an "area" property that is bound to both "width" and "height".  You want to
> write code like:
>
> obj.setWidth(w);
> obj.setHeight(h);
>
> and have only ONE recalculation of the area property happen.  Currently the
> way bindings work the area will be calculated twice.  The intermediate
> calculation is really not a value that you ever want to observe.

Hi Scott,

this is precisely the problem that I'm trying to address here. Now,
the question is whether you have control over the implementation of
obj.

If yes, then it is the same case as the AND gate "motivational
example" from InhiBeans page. You provide a method setSize(w, h) and
use block()/release() to implement it in a way that causes only one
change of the area property.

If you cannot change the implementation of obj, what you can do is to
bind an inhibeans.binding.DoubleBinding to the "area" value, call it
relaxedArea, and listen to that one for all your purposes.
Then you resize obj like this:

relaxedArea.block();
obj.setWidth();
obj.setHeight();
relaxedArea.release();

Only one change of relaxedArea is emitted.

Best,
Tomas

>
> Are there helpers for this sort of situation?  Are there guidelines in the
> JavaFX docs somewhere?
>
> Regards,
>
> Scott
>
>
> On Sat, Dec 14, 2013 at 11:54 PM, Tomas Mikula <tomas.mikula at gmail.com>
> wrote:
>>
>> Hello,
>>
>> I just published a small extension of javafx bindings and properties
>> that can help you reduce redundant recalculations.
>>
>> They provide two additional methods:
>>
>> public void block();
>> public void release();
>>
>> Call p.block() when you suspect your actions will lead to multiple
>> invalidations of p, and call p.release() when you are done and want to
>> deliver a single invalidation notification to p's observers.
>>
>> https://github.com/TomasMikula/InhiBeans
>>
>> Regards,
>> Tomas
>
>