In this latest post to his blog Jani Hartikainen looks at creating “null objects” for your applications – a simple tool that lets you replace multiple evaluation checks with a simple object.

I’ve recently pretty much fell in love with an observer design pattern. You can basically build the whole application on it using awesome power of event driven programming. What exactly is an observer pattern? Basically we have an object you want to monitor ( observe ) for any changes. Most of the time this object just fires out events and we want to listen to them. We can have more objects observing one or more other objects so basically this can be M:N relationship.

p. !