OO jDREW is an Object Oriented extension to jDREW, the Java Deductive Reasoning Engine for the Web. The languages of OO jDREW are dialects of slotted Horn logic with negation as failure: Naf Hornlog RuleML and Naf Hornlog POSL.
OO jDREW is an implementation of a number of features that have been discussed in RIF: positional and slotted Horn logic, RDFS combination, negation as failure, skolemization, and webizing. It has been used for Web rule teaching and prototyping.
Impact on Design
OO jDREW is an example of a design that combines a subset of features desired for RIF.
For More Information
OO jDREW is an open-source system under active development. More information can be found in http://www.jdrew.org/oojdrew/.