[rules-users] Data Modeling for medical expert system

[Vincent Legendre]

You can use dynamic enums in Guvnor (that create dynamic populated 
listboxes).
See guvnor's  doc chapter "1.4.2.4.8. Data enumerations (drop down list 
configurations)"

For your case where number of items are really huge, you may consider 
using custom editors (again, in Guvnor), and implement a js page that 
contains some listbox (as many as level of classification in your 
hierarchy) or directly a tree to select the value. See "custom editor" 
and "working set" part of Guvnor's doc.

If you are under Eclipse, well,  Drools suggestion engine modification 
may be the only way.