Java Semantic Network Programming Series 6: Jena native Reasoning

Rule Description:

A rule is a way to represent knowledge. It generally exceeds the expression capability of owl1. A Semantic web rule is a typical Condition Statement: if-then. New knowledge is added only when a specific statement is true.

The Jena framework comes with a reasoning engine and a recognized rule language. Its advantages are that the jena framework is relatively simple to use and its disadvantages are not w3c reasoning standards.

Ontology modeling:

 

 

1 import com. clarkparsia. sparqlowl. parser. anlr. sparqlOwlParser. string_return; 2 3 import com. hp. hpl. jena. ontology. ontModel; 4 5 import com. hp. hpl. jena. ontology. ontModelSpec; 6 7 import com. hp. hpl. jena. rdf. model. infModel; 8 9 import com. hp. hpl. jena. rdf. model. model; 10 11 import com. hp. hpl. jena. rdf. model. modelFactory; 12 13 import com. hp. hpl. jena. reasoner. reasoner; 14 15 import com. hp. hpl. jena. reaso Ner. rulesys. genericRuleReasoner; 16 17 import com. hp. hpl. jena. reasoner. rulesys. rule; 18 19 20 21 public final class JenaRule 22 23 {24 25 JenaModel jenaModel = null; 26 27 28 29/** 30 31 * jena native inference engine reasoning 32 33 * @ param ruleString 34 35 * @ param filePathString 36 37 */38 39 public void reasoner (String ruleString, string filePathString) 40 41 {42 43 jenaModel = new JenaModel (); 44 45 OntModel ontM Odel = jenaModel. createOntologyModel (OntModelSpec. OWL_DL_MEM, filePathString); 46 47 Reasoner reasoner = new GenericRuleReasoner (Rule. parseRules (ruleString); 48 49 InfModel resulInfModel = ModelFactory. createInfModel (reasoner, ontModel); 50 51 jenaModel. outPut (resulInfModel ); 52 53} 54 55 56 57/** 58 59 * join predicates 60 61 * @ param prefixString 62 63 * @ param predicateString 64 65 * @ return 66 67 */68 69 public String getPredicate (String prefixString, String predicateString) 70 71 {72 73 return "<" + prefixString + predicateString + "> "; 74 75} 76 77} 78 79 80 81 Rule rules: 82 83 @ Test 84 85 public void testJenaRuleReasoner () 86 87 {88 89 JenaModel jenaModel = new JenaModel (); 90 91 jenaModel. outPut (jenaModel. createOntologyModel (OntModelSpec. OWL_DL_MEM, fileString); 92 93 94 95 System. out. println ("After inference"); 96 97 98 99 JenaRule jenaRule = new JenaRule (); 100 101 StringBuffer ruleStringBuffer = new StringBuffer (); 102 103 // rule 1: mother's male compatriot is Uncle 104 105 ruleStringBuffer. append ("[rule1:"); 106 107 ruleStringBuffer. append ("(? Person "+ jenaRule. getPredicate (prefixString," hasParent ") + "? Parent), "); 108 109 ruleStringBuffer. append ("(? Parent "+ jenaRule. getPredicate (prefixString," hasSex ") + "? Sex), "); 110 111 ruleStringBuffer. append (" equal (? Sex, \ "female \"), "); 112 113 ruleStringBuffer. append ("(? Parent "+ jenaRule. getPredicate (prefixString," hasSibling ") + "? Sibling), "); 114 115 ruleStringBuffer. append ("(? Sibling "+ jenaRule. getPredicate (prefixString," hasSex ") + "? Siblingsex), "); 116 117 ruleStringBuffer. append (" equal (? Siblingsex, \ "male \") "); 118 119 ruleStringBuffer. append ("-> "); 120 121 ruleStringBuffer. append ("(? Person "+ jenaRule. getPredicate (prefixString," hasUncle ") + "? Sibling)] "); 122 123 jenaRule. reasoner (ruleStringBuffer. toString (), fileString); 124 125}