See GitHub/DTRules/DTRules
https://DTRules.com 

DTRules is a Decision Table based Rules Engine.

Decision Tables coupled with the use of a Domain Specific Langauge (DSL) 
provide about the best approach around to describe complex policy and logic. 
Decision Tables provide a common representation of policy and rules that 
can be understood by policy experts and developers alike.  A DSL insures 
the syntax for conditions and actions does not become a barrier to policy 
experts in understanding the tables.

DTRules is distributed under the Apache License Version 2.0. 

Copyright 2004-2011 DTRules.com,

DTRules is a Trademark of DTRules.com

Licensed under the Apache License, Version 2.0 (the "License"); you may not 
use this file except in compliance with the License. You may obtain a copy 
of the License at

https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed 
under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR 
CONDITIONS OF ANY KIND, either express or implied. See the License for the 
specific language governing permissions and limitations under the License.