[news.eclipse.tools.emf] Re: ChangeDescription applyAndReverse performan

["Christian W. Damus" <cdamus@xxxxxxxxxxxxx>]

Hi, Bryan,

What do you see as a performance problem?  The ChangeRecorder has a lot 
of work to do in applying itself and in reversing itself.  Presumably, 
your application won't work if it doesn't have these changes to analyze.

I think you'll have to be more specific about what you think is the 
performance problem in order to get a useful response.  For what it's 
trying to do, which is to provide a general-purpose EMF-serializable 
model of changes, the ChangeDescription is pretty efficient.

Cheers,

Christian

Bryan Hunt wrote:
> I've got a performance problem that I've narrowed down to 
> applyAndReverse() on a ChangeDescription.  My code looks something like:
>
> ChangeDescription changes = changeRecorder.endRecording();
> changes.applyAndReverse();
>
> // process changes
>
> change.applyAndReverse();
> changeRecorder.beginRecording(Collections.singleton(this));
>
> I first commented out my processing code and that made no difference in 
> the performance.  As soon as I commented out both calls to 
> applyAndReverse(), my performance problem was gone.  I think my solution 
> will be to write a custom change recorder that that captures the new 
> state instead of the old state.  It won't support rollbacks, but I hope 
> it will be much faster.  Comments?
>
> Bryan