Open Source Blog

Ten Best Open Source Rules Engines* [in alphabetical order]

1. Drools is an Object-Oriented Rule Engine for Java. Drools is an augmented implementation of Forgy's Rete algorithm tailored for the Java language. Adapting Rete to an object-oriented interface allows for more natural expression of business rules with regards to business objects, it’s claimed. More importantly, Drools provides for declarative logic programming and is flexible enough to, “match the semantics of your problem domain”. The various parts that compose a rule may be extended to lend domain-specific sense to the rule.

2. Hammurapi Rules is another JSR-94 compliant rules engine. With Hammurapi Rules Java developers don't need to learn a new rules language -- rules are written in Java. Hammurapi Rules leverages Java language type system and naming conventions to plug rules into its inference engine.

3. JEOPS -- The Java Embedded Object Production System -- is a Java based forward chaining rules engine. It is used to power up the business process by rules in Java Application Servers, client applications, and Servlets.

4. JRuleEngine is another Java rules engine, based on Java Specification Request 94, release 1.1 -- i.e. rules can be loaded by an XML file or by means of JRuleEngine APIs, so rules can be stored externally into a database, too.

5.a. Mandarax is an open source java class library for deduction rules, which provides an infrastructure for defining, managing and querying rule bases; while OpenRules is said to be a full-scale open source Business Rules Management Framework. It is claimed to use the power of MS Excel, Eclipse IDE and open source Java libraries to create, deploy, execute, and maintain different rule engines with complex business logic controlled by business analysts.

6. Open Lexicon is a business rules and business process management tool that “rapidly” develops applications for transaction and process-based applications. It includes a business rules metadata repository, a business rules engine, and a “comprehensive” web-based UI for managing and testing the business rules. It also includes process management tools for orchestrating complex interactions within business rules and business objects.

7. Prova (from Prolog+Java) is a rule-based system for Java and agent scripting and information integration extending the Mandarax engine with a proper language syntax and enhanced semantics. It combines natural syntax and typing of Java with Prolog-style rules and database wrappers. Java calls may include both constructor and method calls as well as access to public variables in classes.

8. SweetRules is an integrated set of tools for semantic web rules and ontologies, revolving around the RuleML (Rule Markup/Modeling Language) emerging standard for semantic web rules, and supporting also the closely related SWRL (Semantic Web Rule Language), along with the OWL standard for semantic web ontologies, which in turn use XML and, optionally, RDF.

SweetRules supports the powerful Situated Courteous Logic Programs extension of RuleML, including prioritized conflict handling and procedural attachments for actions and tests.

The SweetRules project is an international, multi-institutional effort, originated and coordinated by the SweetRules group at MIT Sloan led by Benjamin Grosof, and its creation was funded largely by the DAML (DARPA Agent Markup Language) research program which co-pioneered the Semantic Web.

5b. Take (aka Mandarax Compiler) consists of a scripting language that can be used to define derivation rules, and a compiler that creates executable Java code and deploys it into running systems. Take is inspired by Mandarax, has a similar API but does not use a separate interpreter "inference engine". The deployment process is very similar to how web servers treat server pages. The result is optimized, reflective and easy to maintain code.

9. TermWare is a rule processing engine intended for embedding into Java applications; JLisa is a “powerful” framework for building business rules accessible to Java and is compatible with JSR94 V, the Java Rule Engine API.

10. Zilonis provides a Multithreaded Rules Engine platform and a scripting environment for Java based applications. The core of the Zilonis platform is based on a variation of the forward chaining Rete algorithm described in "Rete: A Fast Algorithm for the Many Pattern/ Many Object Pattern Match Problem", Charles L. Forgy, Artificial Intelligence 19(1982), 17-37.

Because it is multithreaded it is said to be “easy to reuse a set of rules across several concurrent users in a safe way, without creating copies of the rules and the engine, as you would have to do if you were to use other engines.”

*OK, so there are 11, but Take is related to Mandarax.

Any to add? Drop me a line or add a comment.