Re: ChangeNotification framework and Custom EO layout

On Apr 15, 2005, at 9:18 AM, YL wrote:

> Thanks a lot Pierce. Is [spread] an ObjC framework?

  It's an open source generic C thingamabob. http://www.spread.org/

  I think we have some objC wrappers around some of its functionality, 
but they're pretty simple wrappers.

  Basically, it does guaranteed delivery of broadcast messages. In our 
relevant save changes routine, we have a variant called 
[saveChangesAndNotify] that collects the global IDs of all the changed 
objects and broadcasts them on spread after the save completes. Then 
interested parties can listen, and do the invalidate as needed, or 
compare the global ids against a list of object they're watching.

  For instance, on our site (http://www.marketocracy.com) we have a 
virtual ECN that does virtual stock trades, so the WebObjects UI needs 
to know when trades have finished. Similarly, we use the top 100 people 
from our website as a basis for our mutual fund, so the trading 
application needs to know when one of those 100 people have done some 
action on the site.

Pierce