So thinking really long term here. Can we build a "java layer" that provide all the rule functionality we need - but fit ontop of the java language neatly. We'd probably need to allow "rule" keyword and have it in Classes, at the method level. All class members and methods would be available to the rules in that class.

There is this production rule system where you can write your rules embedded in compiling units, and alongside the legacy program units, of a procedural, modular, strongly type HLL, and where you use expressions in the language's own syntax in constraints...

We've been using it ever since 1986. Rabbi Akiva was right, wasn't he ;-)

-W