这是我的代码:
public class FunctionalityCheckTest1 {
InfModel infModel;
Model model = ModelFactory.createDefaultModel();
String NS = "http://myweb.com/vocab#";
@Test
public void playingWithJenaReasoner()
{
Resource alex = this.model.createResource(NS+"Alex");
Resource bob = this.model.createResource(NS+"Bob");
Resource alice = this.model.createResource(NS+"Alice");
Property isFriendOf = this.model.createProperty(NS,"isFriendOf");
alex.addProperty(isFriendOf,bob);
bob.addProperty(isFriendOf,alice);
StmtIterator stmtIterator1 = this.model.listStatements();
while (stmtIterator1.hasNext())
{
System.out.println(stmtIterator1.next());
}
String customRule = "@prefix vocab: <http://myweb.com/vocab#>. " +
"[rule1: (?a vocab:isFriendOf ?b) (?b vocab:isFriendOf ?c) -> (?a vocab:isFriendOf ?c) ]";
List<Rule> rules = new ArrayList<>();
rules.add(Rule.parseRule(customRule));
GenericRuleReasoner reasoner = new GenericRuleReasoner(rules);
reasoner.setDerivationLogging(false);
this.infModel = ModelFactory.createInfModel(reasoner, this.model);
StmtIterator stmtIterator2 = this.infModel.listStatements();
while (stmtIterator2.hasNext())
{
System.out.println(stmtIterator2.next());
}
}
}
在执行playingWithJenaReasoner()函数时,它会抛出错误:
com.hp.hpl.jena.reasoner.rulesys.Rule $ ParserException:预期&#39;(&#39;在条款开头,找到词汇:
来自行规则.add (Rule.parseRule(customRule));
如果我将这些更改添加到上面的代码中,一切正常
PrintUtil.registerPrefix("vocab",NS);
String customRule = "[rule1: (?a vocab:isFriendOf ?b) (?b vocab:isFriendOf ?c) -> (?a vocab:isFriendOf ?c) ]";
这个怎么回事?
String customRule = "@prefix vocab: <http://myweb.com/vocab#>. " +
"[rule1: (?a vocab:isFriendOf ?b) (?b vocab:isFriendOf ?c) -> (?a vocab:isFriendOf ?c) ]";
在这个Jena Documentation中,他们提到了@prefix with rule。我哪里做错了?
答案 0 :(得分:2)
我遇到了你今天遇到的同样的问题,这似乎是方法
public static List<Rule> parseRules(String source)
不允许字符串中包含前缀。我不确定这是否是此方法的错误或功能。
但是,如果您在规则文件中声明规则并通过
加载它 public static List<Rule> rulesFromURL(String uri)
您应该能够加载包含前缀的规则。
这是一个测试是否有效的小例子。它假定您将本体存储在文件系统的某个位置,并在类路径中包含名为jena.rule
的规则文件:
public class JenaRuleTest {
public static void main(String[] args) throws UnsupportedEncodingException {
OntModel model = ModelFactory.createOntologyModel();
model.read("C:\\path\\to\\ontology\\ontology.ttl");
String ruleResourceStr = JenaRuleTest.class.getResource("/jena.rule").toString();
Reasoner reasoner = new GenericRuleReasoner(Rule.rulesFromURL(ruleResourceStr));
reasoner.setDerivationLogging(true);
InfModel inf = ModelFactory.createInfModel(reasoner, model);
inf.write(System.out, "TURTLE");
}
}
更详细的示例如何在此处找到:http://tutorial-academy.com/jena-reasoning-with-rules/
Rule
课程的文档可在此处找到:https://jena.apache.org/documentation/javadoc/jena/org/apache/jena/reasoner/rulesys/Rule.html
希望如果有人遇到这个问题会有所帮助。
问候