CoffeeFilter

CoffeeFilter

is a lightweight java validation and data object creation framework that works off of incoming request URL parameters. It is intended for JSP web application. CoffeeFilter is basically a Filter pattern product.

In it's most basic usage

CoffeeFilter

can be used to validate that parameters required for the view are included in the request URL string. In more advanced usage, it can generate data objects based on URL parameters before hitting the view; ie pre-processing data based on URL parameters to resolve data. Data objects are really just JavaBeans that implement an interface.

I've thought about this a lot after a friend, ML, smartly questioned the intent behind this framework... It is two fold:

• Create a URL parameter validation framework that was simple to use. Basically, the idea is that parameter validation in every page is overhead that you don't need to deal with! URL parameter validation is easily (re)moved into a central location that works without having to know about your page layouts, ie it works based on config files and dependency injection.
• The URL parameter validation is of, admittidly, little use; basically, why bother with URL parameters if you could just create a separate page, eh? Almost. What if you need to do some pre-processing based on the URL parameters before you actually hit the page. Imagine somebody linking into a distributed application using URL parameters that are user credentials that resolve their info (a lame example, I know). You basically need the lookup to happen before you hit the page that will display said info. If this is your case, then this framework could be of use.

There are a lot of other great tools out there that do similar things, but I've yet to find one that matched my needs.
Here is a run down of pros and cons: