Re: [Repast-developer] Scheduler trip-up

[Nick C. <nic...@ve...>]

Walter,

Precalculating the size of the loop is probably an example of a  
premature optimization. The work around when removing actions is to  
schedule the action removal for some tick time immediately after the  
action that causes the removal.

Nick

On Jul 9, 2007, at 5:05 PM, Beyeler, Walter E wrote:

> My application makes heavy use of the Schedule.removeAction  
> method.  I am regularly getting an array index out of bounds  
> exception due to an attempt to get at a missing array element:
>
> Exception in thread "Thread-2" java.lang.IndexOutOfBoundsException:  
> Index: 1, Size: 1
>         at java.util.ArrayList.RangeCheck(ArrayList.java:546)
>         at java.util.ArrayList.get(ArrayList.java:321)
>         at uchicago.src.sim.engine.ScheduleGroup.execute(Unknown  
> Source)
>         at uchicago.src.sim.engine.RandomScheduleGroup.execute 
> (Unknown Source)
>         at uchicago.src.sim.engine.Schedule.execute(Unknown Source)
>         at uchicago.src.sim.engine.BaseController$1.run(Unknown  
> Source)
>         at java.lang.Thread.run(Thread.java:595)
>
>
> Looking at the code for ScheduleGroup.execute
>
>   public void execute() {
>     for (int i = 0, n = actions.size(); i < n; i++) {
>       ((BasicAction)actions.get(i)).execute();
>     }
>   }
>
> it seems that if the executed action happens to modify "actions" by  
> deletion then the variable "n" will still reflect the original size  
> and so allow a bad address.  It looks like this iteration  
> construct, rather than one using the Iterator class, helps get  
> around the concurrent modification exception that would otherwise  
> occur when I try to change the schedule.  If you mean to allow  
> schedule changes within BasicAction.execute() shouldn't the size be  
> re-set within the loop, or some other precaution taken?
>
> Thanks
>
>  -- Walt
>
> ---------------------------------------------------------------------- 
> ---
> This SF.net email is sponsored by DB2 Express
> Download DB2 Express C - the FREE version of DB2 express and take
> control of your XML. No limits. Just data. Click to get it now.
> http://sourceforge.net/powerbar/db2/ 
> _______________________________________________
> Repast-developer mailing list
> Rep...@li...
> https://lists.sourceforge.net/lists/listinfo/repast-developer