customising problems view in Eclipse 3.2

[Sarah Connor]

Hi guys,
I'm just starting to try to figure out how to customise the Problems view in eclipse so that e.g. if Have an object A who's value range is from 3-5 and the value is set to 6 that a warning/error will appear in the Problems view.

I've been searching high and low both around this forum and the internet in general.

If anyone could point me in the direction of where to start or even what "buzz" words I should be using I'd be most grateful.
Regards,
Sarah K