Layer Supertype
A type that acts as the supertype for all types in its layer.
It's not uncommon for all the objects in a layer to have methods you don't want to have duplicated throughout the system. You can move all of this behavior into a common Layer Supertype.
for more details go to Chapter 18 of the online ebook at oreilly.com
This pattern is part of Patterns of Enterprise Application Architecture
05 March 2003