Jena rules is Java-based framework for building Semantic Web applications. An environment for RDF, RDFS and OWL, SPARQL and includes a rule-based inference engine. Three kind of rules (according with their execution model): forward rules, backward rules and hybrid rules.
Jena Rules provides three mechanism of rule execution:
Backward Chaining Rules - are identified by using
<-. These rules are interpreted as queries and the rule head (the conclusion part) contains a single atom which cannot be a built-in. The body (the condition part) is a conjunction between one or more triple patterns and/or built-ins.Forward Chaining Rules - are identified by using
->. They are executed by a forward engine and both the head and body may contain of conjunction of atoms.Hybrid Rules - consists in using one or more backward chaining rules in the head of a forward chaining rule.
