Re: [Fresco-devel] problems with dead graphics again (sorry)

[email protected] wrote:
> On Wed, Oct 29, 2003 at 08:46:52PM -0500, Stefan Seefeld wrote:
> 
>>in a potentially distributed environment like this, where every object 
>>could be
>>physically located on a different machine, every method invocation may 
>>throw.
> 
> so... we have to be paranoid on every interface call *g*

well, I wouldn't call it paranoid. It's just a different mindset :-)

>>The Traversal::update() call that is running into this is just updating
>>a cache. As such, it should be totally transparent to the user. This means
>>that if we can't update the cache, we must throw it out and start anew, but
>>otherwise ignore the exception.
> 
> this means we don't do anything in TraversalImpl because the Traversal
> corrupting just it's own stack of graphic-nodes?
> we catch the exception in PositionalFocus and if it happens we delete the
> Traversal and create a new? or we handle it inside TraversalImpl... 
> cleaning the whole stack/cache... and try to fill it new from beginning?

yes, kinda. On each positional event we have to figure out which node
should receive it. That process is called picking. But instead of
starting over with a new traversal we look at the last memento and try
to recover from there. That's the cache we are talking about.

Stefan