Specification Based Factory

Cool stuff today.

Simon and James came up with a new use for the Specification pattern. They combined it with the Factory pattern.

Basically, we need to find a class under some pretty heavy conditions (OK maybe we need a strategy pattern). They look up the class in a Map, indexed by a Specification object. They iterate over the map evaluating the specification, when one return trues they poof up a new instance of the class contained in the value.

Nice explicit code, with each rule contained in its own specification object.

I love simple stuff.