How to design/develop a customer segmentation framework in Java?

How to design/develop a customer segmentation framework in Java?

I have a requirement to develop a basic customer segmentation framework in Java that should allow to use Customer's Attributes and Customer's Purchase Transaction Activities/Attributes to be used to create customer segments.

The major questions I have are:

1) How (which pattern / format) and where(database?) to store the rules that define each segment?

2) Which approach would allow the segmentation rules to be stored in a way that can be run by job/worker to identify the customers that belong to the segment?

3) How to run the segmentation rules/jobs continuously/near real time ?

4) How to handle the variety of attributes that can be part of the segmentation rule avoiding hard coding it too much in away that allow to handle new/future attributes that will come?

Thanks