Hi,
The documentation on the rule system is:
http://jena.apache.org/documentation/inference/index.html#rules
Though I imagine if you've seen that already.
That should be enough to see how to have multiple rules in one rule set
and how to write forward rules instead of backward rules.
As to passing models around I'm not sure what documentation would be
helpful. Your "applyRule" function returns an InfModel but takes a
String argument. You could instead have it take a Model as an argument
and have your "infer*" functions consume and generate Models.
Dave
On 12/12/12 08:48, Oana Ureche wrote:
Hi Dave,
Well.. I don't know the library well.
Thank you for the input. Is there any documentation or tutorials about what
you're recommending?
Thank you,
Oana.
Sent from my iPhone
On 12/12/2012, at 7:31 PM, Dave Reynolds <[email protected]> wrote:
On 12/12/12 04:07, Oana Ureche wrote:
Hi all,
There is a shortcoming in Jena. Mainly the fact that it cannot handle complex
rules.. i.e. throwing the following exception
Exception in thread "main"
com.hp.hpl.jena.reasoner.rulesys.impl.LPRuleSyntaxException: Syntax error in backward
rule: rule1
Rule too complex for current implementation
Rule clauses are limited to 15 permanent variables
So I have decided to split the complex rule into smaller rules. Then apply a
small rule to a dataset, which results into a bigger dataset, then apply the
next small rule to the bigger dataset and so on and so forth.. Code looks like
the following:
Some suggestions here ...
Firstly, if you can split your big rule into smaller rules then why not do so
within one rule set? I don't follow the need to have separate rule sets.
Secondly, since your are running the inference to completion then forward rules
would be both higher performance and can handle more complex rules then
backward rules.
Thirdly if you are going to split your rules into different rule sets then just
pass the models around. I don't understand why you are serializing the models
to strings and then deserializing them. Seems unnecessary.
Dave
private static InfModel applyRule(String dataset, String
filepath) {
InputStream stream = new ByteArrayInputStream(dataset.getBytes("UTF-8"));
Model instances = ModelFactory.createDefaultModel();
instances.read(stream, null);
Reasoner reasoner = new GenericRuleReasoner(Rule.rulesFromURL(filepath));
reasoner.setDerivationLogging(true);
return ModelFactory.createInfModel(reasoner, instances);
}
private static String inferConnName(String dataset) {
InfModel inf = applyRule(dataset, "file:rules/conn_name.txt");
ByteArrayOutputStream out = new ByteArrayOutputStream();
inf.write(out, "RDF/XML");
return out.toString();
}
private static String inferStatementName(String dataset) {
InfModel inf = applyRule(dataset, "file:rules/statement_name.txt");
ByteArrayOutputStream out = new ByteArrayOutputStream();
inf.write(out, "RDF/XML");
return out.toString();
}
private static void getVuln(String dataset) {
String conn_name_dataset = inferConnName(dataset);
String statement_name_dataset = inferStatementName(conn_name_dataset);
InfModel inf = applyRule(statement_name_dataset, "file:rules/param.txt");
//print out the statements in the model
StmtIterator iter = inf.listStatements();
while (iter.hasNext()) {
Statement stmt = iter.nextStatement(); // get next statement
............................
}
I was wondering if there is a better way to do this?
Thank you,
Oana.
