Hello, i just created a JIRA ticket and i attached a patch corresponding to the modifications discussed previously:
https://issues.apache.org/jira/browse/JENA-863 <https://issues.apache.org/jira/browse/JENA-863> Regards Seb Sébastien BOULET LEAD DÉVELOPPEUR intactile DESIGN Création d’interfaces + subtiles 04 67 52 88 61 09 50 12 05 66 20 rue du carré du roi 34000 MONTPELLIER France www.intactile.com <http://intactile.com/> Les informations contenues dans cet email et ses documents attachés sont confidentielles. Elles sont exclusivement adressées aux destinataires explicitement désignés ci-dessus et ne peuvent être divulguées sans consentement de son auteur. Si vous n'êtes pas le destinataire de cet email vous ne devez pas employer, révéler, distribuer, copier, imprimer ou transmettre le contenu de cet email et devez le détruire immédiatement. > Le 21 janv. 2015 à 12:34, Dave Reynolds <[email protected]> a écrit : > > No "red" in the plain text copy I received :) but I think I can see the > changes you are proposing. They do look safe in principle (aside from some > missing "{}"). > > As we discussed before, there is no guarantee you will receive all the > removal messages so whether this facility will achieve what you desire is not > clear to me. However, it does give an extension point for people who want to > experiment in this area and should not affected existing usage. > > Happy for you to submit a tested patched as a JIRA so people can check it. > I'm about to go on leave so will not be able to look it instantly myself. > > Dave > > > On 21/01/15 10:50, Christophe FAGOT [intactile DESIGN] wrote: >> Hi all, hi Dave, >> >> back to this old discussion, in order to increase the BuiltIn behaviour by >> our side, but while preserving the actual behaviour of the existing BuiltIn >> of Jena and those developped by third parties, we would like to propose the >> following patches. Our aim is to be able to send the removed context to some >> rules handle by a RETE engine (while it's not possible for the time being). >> >> First, we need an interface extending the current BuilIn one and provide a >> method called when removed contexts have to be indicated. >> >> public interface ReversibleBuiltIn extends BuiltIn { >> /** >> * This method is invoked when the builtin is called in a rule head with >> a removed context. >> * Such a use is only valid in a forward rule. >> * @param args the array of argument values for the builtin, this is an >> array >> * of Nodes. >> * @param length the length of the argument list, may be less than the >> length of the args array >> * for some rule engines >> * @param context an removed context giving access to other relevant data >> */ >> public void reverseHeadAction(Node[] args, int length, RuleContext >> context); >> } >> >> Then, when need to define when to call the reverseHeadAction method, we >> propose to complete RETEConflictSet::execute as following (changes are in >> bold red) : >> >> public static void execute(RETERuleContext context, boolean isAdd) { >> Rule rule = context.getRule(); >> BindingEnvironment env = context.getEnv(); >> ForwardRuleInfGraphI infGraph = >> (ForwardRuleInfGraphI)context.getGraph(); >> if (infGraph.shouldTrace()) { >> logger.info("Fired rule: " + rule.toShortString()); >> } >> RETEEngine engine = context.getEngine(); >> engine.incRuleCount(); >> List<Triple> matchList = null; >> if (infGraph.shouldLogDerivations() && isAdd) { >> // Create derivation record >> matchList = new ArrayList<>(rule.bodyLength()); >> for (int i = 0; i < rule.bodyLength(); i++) { >> Object clause = rule.getBodyElement(i); >> if (clause instanceof TriplePattern) { >> matchList.add(env.instantiate((TriplePattern)clause)); >> } >> } >> } >> for (int i = 0; i < rule.headLength(); i++) { >> Object hClause = rule.getHeadElement(i); >> if (hClause instanceof TriplePattern) { >> Triple t = env.instantiate((TriplePattern) hClause); >> // Used to filter out triples with literal subjects >> // but this is not necessary >> // if (!t.getSubject().isLiteral()) { >> // Only add the result if it is legal at the RDF level. >> // E.g. RDFS rules can create assertions about literals >> // that we can't record in RDF >> if (isAdd) { >> if ( ! context.contains(t) ) { >> engine.addTriple(t, true); >> if (infGraph.shouldLogDerivations()) { >> infGraph.logDerivation(t, new >> RuleDerivation(rule, t, matchList, infGraph)); >> } >> } >> } else { >> if ( context.contains(t)) { >> // Remove the generated triple >> engine.deleteTriple(t, true); >> } >> } >> // } >> } else if (hClause instanceof Functor && isAdd) { >> Functor f = (Functor)hClause; >> Builtin imp = f.getImplementor(); >> if (imp != null) { >> imp.headAction(f.getBoundArgs(env), f.getArgLength(), >> context); >> } else { >> throw new ReasonerException("Invoking undefined Functor >> " + f.getName() +" in " + rule.toShortString()); >> } >> else if (hClause instanceof Functor && !isAdd) { >> Functor f = (Functor)hClause; >> BuiltIn imp = f.getImplementor(); >> if (imp != null && imp instanceOf ReversibleBuiltIn ) { >> >> ((ReversibleBuiltIn)imp).reverseHeadAction(f.getBoundArgs(env), >> f.getArgLength(), context); >> } >> } else if (hClause instanceof Rule) { >> Rule r = (Rule)hClause; >> if (r.isBackward()) { >> if (isAdd) { >> infGraph.addBRule(r.instantiate(env)); >> } else { >> infGraph.deleteBRule(r.instantiate(env)); >> } >> } else { >> throw new ReasonerException("Found non-backward subrule >> : " + r); >> } >> } >> } >> } >> >> >> Does it sounds good for you ? If yes, we will do these improvements, and a >> ticket in Jira and send the patch for validation. >> >> Best regards, >> >> Chris. >> >> Christophe FAGOT, PhD >> RESPONSABLE R&D INFORMATIQUE >> >> intactile DESIGN >> Création d’interfaces + subtiles >> +33 (0)4 67 52 88 61 >> +33 (0)9 50 12 05 66 >> 20 rue du carré du roi >> 34000 MONTPELLIER >> France >> www.intactile.com >> >> Hugh MacLeod : "It's not what the software does, it's what the user does" >> >> Les informations contenues dans cet email et ses documents attachés sont >> confidentielles. Elles sont exclusivement adressées aux destinataires >> explicitement désignés ci-dessus et ne peuvent être divulguées sans >> consentement de son auteur. Si vous n'êtes pas le destinataire de cet email >> vous ne devez pas employer, révéler, distribuer, copier, imprimer ou >> transmettre le contenu de cet email et devez le détruire immédiatement. >> >>> Le 20 mars 2014 à 16:20, Dave Reynolds <[email protected]> a écrit : >>> >>> >>> On 20/03/14 10:59, Christophe FAGOT wrote: >>>> >>>> Le 20 mars 2014 à 11:20, Dave Reynolds <[email protected]> a écrit >>>> : >>>> >>>>> >>>>> On 20/03/14 09:46, Christophe FAGOT wrote: >>>>>> >>>>>> Le 19 mars 2014 à 18:46, Dave Reynolds <[email protected]> a >>>>>> écrit : >>>>>> >>>>>>> >>>>>>> On 19/03/14 16:46, Christophe FAGOT wrote: >>>>>>>> Hi Jena folks, >>>>>>>> >>>>>>>> since I need to use Jena with its RETEEngine, I’m actually >>>>>>>> investigating what is actually feasible / usable with this engine >>>>>>>> functionalities. >>>>>>>> >>>>>>>> I would like to develop my own BuiltIn, used in the head of a forward >>>>>>>> rule, and doing some actions when a new rule context appears (due to >>>>>>>> triples adding) for the body rule, while doing some other actions when >>>>>>>> a rule context disappears (dur to triples removal) for this body rule. >>>>>>>> >>>>>>>> It appears in the RETEConflictSet (line 180) that a BuiltIn can >>>>>>>> receive only … added RETERuleContext. Hence a BuiltIn action can only >>>>>>>> be called when a RETERuleContext is added, never when a >>>>>>>> RETERuleContext is removed. >>>>>>>> >>>>>>>> Is their a reason for that ? >>>>>>> >>>>>>> The existing head builtins expect to only be fired when a potitive >>>>>>> deduction is made. This is a legacy of the fact that the rule system >>>>>>> was designed for monotonic inference and all the remove/non-monotonic >>>>>>> processing is a hack. >>>>>> >>>>>> I don’t see the relationship between monotonic inference and remove >>>>>> prohibited. A monotonic inference only means that when adding some facts >>>>>> in the knowledge base, the previous inferred data can’t be removed, >>>>>> while when removing some facts, new facts can’t be produced. And this is >>>>>> exactly what Jena Rete engine perfectly does with « standard » triple >>>>>> patterns. But when the head is a BuiltIn, that BuiltIn does not have a >>>>>> single chance to act the same way. The BuildIn can only react to added >>>>>> triples. And the only mandatory thing for a BuiltIn is to declare is it >>>>>> is monotonic or not. But it’s behavior and the triples it adds/removes >>>>>> in the inference graph are never verified to check if it really has a >>>>>> (non-)monotonic behavior. But this is another story. >>>>> >>>>> The point is that builtins in the head are only useful if they have some >>>>> side effect. Jena indeed handles removes when the rules are monotonic. As >>>>> soon as you have side-effecting builtins then all bets are off. Even if a >>>>> builtin's effect is reversible (which I take to be the case you are >>>>> interested in) it's hard to guarantee all the necessary rules will fire >>>>> in "remove" mode in the way you expect without the rule equivalent of >>>>> reference counting. >>>> >>>> Absolutely agree. Would you be open to some little modifications in the >>>> RETE classes source code, if that modifications improve the ability to >>>> extend the RETE behavior (or to correct the problem of memory >>>> consumption), while preserving the actual behavior of existing rules sets >>>> using BuiltIn (hence, receiving only added data) ? >>> >>> Sure, patches welcome. >>> >>> I believe the right workflow would be to open a jira entry/ies for your >>> enhancement and attach the changes as patch fines. >>> >>> Warning: I'm petty overloaded right now [*] so may need prompting to review >>> any patches. >>> >>> Dave >>> >>> [*] For values of "right now" that seem to be depressingly permanent! >> >>
