UML + some UI

[Tony Hardie-Bick]

Peter Korsten wrote:
> At work, I'm to write a server application that sends and receives SMS 
> messages,possibly tens of thousands at the time. Obviously, sending out 
> 12,000 messages from one application must not interfere with sending one 
> message with a password reminder (which must be nearly instantaneous).
> 
> We've been talking about it, coming up wioth a design, ditching it, 
> until we ended up with just a single, giant table for all incoming and 
> outgoing messages. Configuration will be largely in the database, to 
> enforce referential integrity. Making sure that transactions work 
> properly ensures that you can cluster the application without a problem.
> 
> If one or more new messages come in, the application starts a new thread 
> for each destination (which means a pool of connectiins to the SMSC, the 
> SMS server). In each of those threads, the relevant messages are loaded 
> from the database, and they are being sent to a thread pool (a Java 5 
> feature), the size of the thread pool being the size of the SMSC 
> connection pool for that destination.
> 
> So we have one event starting one or more threads, each of those threads 
> starting a number of threads themselves.
> 
> So there are dozens of threads running, but the whole thing can be 
> described in two UML activity diagrams.
> 
> I thinlk it's actually a pretty simple design - and that's the sort of 
> design I prefer.

Groovy. Polyphonic note assignment on steroids!