I am using the Jena GenericRuleReasoner. It is invoked in an Eclipse
environment. After creating an InfModel by calling
ModelFactory.createInfModel(reasoner, ontModel), I call
QueryExecutionFactory.create(QueryFactory.create(query, Syntax.syntaxARQ,
infModel). I then set the timeout by calling
queryExecution.setTimeout(timeoutTime). I then start to iterate over the
ResultSet returned by queryExecution.execSelect() by calling the
ResultSet's hasNext() method.
I would like to be able to cancel or abort if inference takes an excessive
amount of time. However, the call to the ResultSet hasNext() method results
in a call to FBRuleInfGraph find(s, p, o), which ultimately ends up at
LPBRuleEngine pump(gen), where gen is an LPInterpreterContext. Neither the
QueryExecution timeout nor a call to QueryExecution abort() has any effect
because control never gets out of the pump method. Is there a way to
terminate reasoner execution gracefully? If not, could one be implemented
by putting a check for cancellation, perhaps in the "while(!gen.isReady())"
or like the periodic check
if (count % CYCLES_BETWEEN_COMPLETION_CHECK == 0) {
....
}
and return cancelled?
There does not seem to be any way to terminate inference currently, even
though it is running as a separate Eclipse Job, so a separate thread. All
documentation that I find says that the process needs to check to see if it
has been cancelled; it can't be killed from outside.
Andy Crapo
