Event, Message based communication

[a1prashant]

Friends,

There are 2-3 modules in my java project. UI module creates some events which I need to propagate to Logic module where "what to do next" is decided.
Logic module has a thread running and can take care of multiple such Events/Messages that come from other modules.

I want to use Message (i.e. ID, object) based communication between these modules.
Is there any pattern-based or standard method I can follow?

I know JMS (Java message servicing) is very bulky - for P2P communication - and not for this small program. So that is not the solution.

Regards,
PG

[Singing Boyo]

Its actually a very common design pattern. Usually, what you do is create a listener interface, which is implemented by classes that need to know about events. The class that is being listened to would provide an addXXXListener method, and probably a removeXXXListener method as well, and send the appropriate events to the listeners. The pattern is used by your UI as well, if you're using ActionListener, which I would guess is the case.

Many of my projects now hit at least 5 xxxListener interfaces, just for core UI components to ensure that they update on time.

In your case, as your logic module is running on a different event, you'll want the listener methods to queue events to be handled by the logic thread. However, unless your calculations to decide what to do next can take a long time, I'd suggest getting rid of that extra thread, as it will just complicate your code.

Finally, there is another pattern, as used by Java NIO with its selectors. That one you'll have to look up, as its much more complicated. It only works with multiple threads.

[JosAH]

Please don't double post: standard communication protocol among modules

kind regards,

Jos

[Singing Boyo]

Hmm... I think I'll copy mine into the one in advanced java. This could get complicated...

Thanks for the warning Jos.