User-defined Rule Reasoning in Java

Support
1

Can we load a data file wich contains a rule by using Java ?
I try it with Jena and SNARL but it seems impossible.

Sincerely.

2

There should be no issues loading turtle files with rules in them via whatever method. What is the error you are seeing?

3

My ttl file is:

@prefix db: http://data/# .
@prefix fx: http://fx/# .
@prefix rdfs: http://www.w3.org/2000/01/rdf-schema# .

db:Jean a fx:male ,
fx:parent;
rdfs:label "Jean" .

IF {
?x a fx:male, fx:parent .
}
THEN {
?x a fx:father
}
Blockquote
db:Louis a fx:male .
db:Louis a fx:parent .

the error is:

Exception in thread "main" org.apache.jena.riot.RiotException: [line: 9, col: 1 ] Out of place: [KEYWORD:IF]
at org.apache.jena.riot.system.ErrorHandlerFactory$ErrorHandlerStd.fatal(ErrorHandlerFactory.java:136)
at org.apache.jena.riot.lang.LangEngine.raiseException(LangEngine.java:165)
at org.apache.jena.riot.lang.LangEngine.exceptionDirect(LangEngine.java:158)
at org.apache.jena.riot.lang.LangEngine.exception(LangEngine.java:151)
at org.apache.jena.riot.lang.LangTurtleBase.triplesSameSubject(LangTurtleBase.java:238)
at org.apache.jena.riot.lang.LangTurtle.oneTopLevelElement(LangTurtle.java:46)
at org.apache.jena.riot.lang.LangTurtleBase.runParser(LangTurtleBase.java:89)
at org.apache.jena.riot.lang.LangBase.parse(LangBase.java:42)
at org.apache.jena.riot.RDFParserRegistry$ReaderRIOTLang.read(RDFParserRegistry.java:175)
at org.apache.jena.riot.RDFDataMgr.process(RDFDataMgr.java:905)
at org.apache.jena.riot.RDFDataMgr.read(RDFDataMgr.java:256)
at org.apache.jena.riot.RDFDataMgr.read(RDFDataMgr.java:242)
at org.apache.jena.riot.adapters.RDFReaderRIOT.read(RDFReaderRIOT.java:69)
at triplestores.StardogJena.insertWithRule(StardogJena.java:73)
at controllers.JenaControllerSD.insertModelWithRulesOnStardog(JenaControllerSD.java:336)
at main.Triples.main(Triples.java:183)

4

I apologize, I should have been more clear… Uploading a ttl file with inline rules like this will NOT work in Sesame/Jena/RDF4J because it’s non-standard Turtle. Via SNARL, however, I am able to load the rule in and query it just fine:

public static void main(String... args) {
		try (Connection conn = Utils.getDefaultConnection("support")) {
			conn.begin();
			conn.add().io().file(new File("/Users/stephen/support/community/rules.ttl").toPath());
			conn.commit();

			try (TupleQueryResult res = conn.select("SELECT * WHERE { ?f a <http://fx/#father> }").reasoning(true).execute()) {
				while (res.hasNext()) {
					System.out.println(res.next().getBinding("f"));
				}
			}
		}
	}

f=http://data/#Jean
f=http://data/#Louis

Just a couple of gotchas to watch out for:

  1. It might be Discourse eating the formatting, but be sure that your prefixes are surrounded with <>
  2. This also might be Discourse, but your “Jean” label looks to have ‘smart quotes’ instead of standard " characters, making the turtle invalid
1 Like
5

Thank you very much it seems to work correctly

6

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