Github user afs commented on a diff in the pull request:
https://github.com/apache/jena/pull/47#discussion_r29499213
--- Diff:
jena-core/src/main/java/com/hp/hpl/jena/reasoner/rulesys/impl/LPBRuleEngine.java
---
@@ -252,19 +272,31 @@ public synchronized void tablePredicate(Node
predicate) {
/**
* Return a generator for the given goal (assumes that the caller
knows that
* the goal should be tabled).
+ *
+ * Note: If an earlier Generator for the same <code>goal</code> exists
in the
+ * cache, it will be returned without considering the provided
<code>clauses</code>.
+ *
* @param goal the goal whose results are to be generated
* @param clauses the precomputed set of code blocks used to implement
the goal
*/
- public synchronized Generator generatorFor(TriplePattern goal,
List<RuleClauseCode> clauses) {
- Generator generator = tabledGoals.get(goal);
- if (generator == null) {
- LPInterpreter interpreter = new LPInterpreter(this, goal,
clauses, false);
- activeInterpreters.add(interpreter);
- generator = new Generator(interpreter, goal);
- schedule(generator);
- tabledGoals.put(goal, generator);
- }
- return generator;
+ public synchronized Generator generatorFor(final TriplePattern goal,
final List<RuleClauseCode> clauses) {
+ return getCachedTabledGoal(goal, new Callable<Generator>() {
+ @Override
+ public Generator call() {
+ /** FIXME: Unify with
#generatorFor(TriplePattern) - but investigate what about
+ * the edge case that this method might have
been called with the of goal == null
+ * or goal.size()==0 -- which gives different
behaviour in
+ * LPInterpreter constructor than through the
route of
+ * generatorFor(TriplePattern) which calls a
different LPInterpreter constructor
+ * which would fill in from RuleStore.
+ */
--- End diff --
I don't know enough about the rules engine to comment. We need another
reviewer here.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
