Example XML Rules document: <user> <username> <not-null/> <capitals value="false"/> <max-length value="15"/> </username> <email> <not-null/> <isEmail/> <max-length value="40"/> </email> </user> How do I implement this? I'm starting from scratch, what I currently have is a User-class, and a UserController which saves the User object in de DB (through a Service-layer and Dao-layer), basic Spring MVC. I can't use Spring MVC Validation however in our Model-classes, I have to use an XML document so an Admin can change the rules I think I need a pattern which dynamically builds an algorithm based on what is provided by the XML Rules document, but I can't seem to think of anything other than a massive amount of if-statements. I also have nothing for the parsing yet and I'm not sure how I'm gonna (de)couple it from the actual implementation of the validation-process.