You are viewing a plain text version of this content. The canonical link for it is here.
Posted to users@jena.apache.org by L B <da...@gmail.com> on 2023/01/24 19:30:21 UTC
Builtin primitives in rule not triggered
Per Jena rule syntax and structure, I can use builtin primitives in the
rule.
*term* := (*node*, *node*, *node*) // triple pattern
or (*node*, *node*, *functor*) // extended triple pattern
or builtin(*node*, … *node*) // invoke procedural primitive
I have tried the following built-ins, but none of them could be triggered.
[ test1: makeTemp(?x) -> print("makeTemp test") ]
[ test1: unbound(?x) -> print("unbound test") ]
[ test1: bound(?x) -> print("bound test") ]
[ test1: now(?x) -> print("now test") ]
However, if I added one triple ahead as below. It works.
[ test1: (:User rdf:type ?y) makeTemp(?x) -> print("makeTemp test") ]
Where :User is an individual in the system.
Re: Builtin primitives in rule not triggered
Posted by Dave Reynolds <da...@gmail.com>.
On 31/01/2023 22:25, L B wrote:
> The current implementation only matches the triples when facts are
> updated.
Correct, that's kind of the point of it.
> Do we have any plan to support built-in primitives?
? There are built in primitives and you can write your own primitives.
That doesn't change the structure of rule evaluation
> such as the rule below, the rule will be evaluated when uri1 or uri2 is
> updated.
>
> [rule1:
> built-inName1(uri1, built-inName2(uri2)) -> xxxx
> ]
What does it mean to "update a uri"? Or match on one for that matter?
RDF is a set of triples, uris are just one of the types of atom that can
be used to construct triples but don't themselves change. It's only
facts about them that change. So if you want to fire some rule when a
fact about either uri1 or uri2 changes then that's just:
(uri1 ?p1 ?o1), (uri2 ?p2 ?o2), f(uri1, uri2, ?result) -> x
The rule systems in Jena were developed to enable deductions to be made
over a set of triples. If the base triples change the rules are supposed
to figure out the new deduced triples. That's it.
They were designed to be relatively efficient when you are just adding
more facts, and monotonic. So when you add more facts (triples) only the
new facts need to be processed and you only get more deduced triples
added, no old deductions gets removed. Over time we added some
non-monotonic features (e.g. "remove", cough) because people found that
useful but the system wasn't designed with the in mind and those
non-monotonic features can be clunky.
If you are doing something too far outside this design centre then, as I
said before, you may be better off using the generic listener events.
Dave
>
> Dave Reynolds <da...@gmail.com> 于2023年1月28日周六 04:56写道：
>
>> Once a rule has triggered it will only retrigger if the data changes in
>> a way that affects that rule's bindings. So a rule which doesn't match
>> anything on the LHS will not normally be retriggered.
>>
>> The behaviour you are seeing is as expected for the rule system.
>>
>> If your goal is to do something whenever data changes irrespective of
>> what the change is then you either need a rule with a pattern that will
>> match any data i.e. (?s ?p ?o) or don't use rules but use graph
>> listeners via the GraphEventManager interface.
>>
>> Dave
>>
>> On 27/01/2023 21:31, L B wrote:
>>> Thanks for the test code.
>>>
>>> Please correct me if I am wrong. Per the doc of listStatements: Find all
>>> the statements matching a pattern.
>>>
>>> My problem is that when I update the facts, this rule is not be triggered
>>> (executed). I assume this rule will be triggered every time when the
>> fact
>>> is updated.
>>>
>>> On the other hand, a leading triple can bypass it. For example
>>>
>>> [test1: (a b ?c) now(?x) -> print(\"now test\") ]. When you update
>> triple
>>> (a, b, xxx), the rule will be executed.
>>>
>>> Lorenz Buehmann <bu...@informatik.uni-leipzig.de> 于2023年1月26日周四
>> 23:13写道：
>>>
>>>> I cannot reproduce this. For example, the test code
>>>>
>>>>
>>>> public static void main(String[] args) {
>>>> String raw = "<http://ex.org/a> <http://ex.org/p>
>>>> <http://ex.org/b> .";
>>>> Model rawData = ModelFactory.createDefaultModel();
>>>> rawData.read(new StringReader(raw), null, "N-Triples");
>>>> String rules =
>>>> "[test1: now(?x) -> print(\"now test\") ]";
>>>> Reasoner reasoner = new
>>>> GenericRuleReasoner(Rule.parseRules(rules));
>>>> InfModel inf = ModelFactory.createInfModel(reasoner, rawData);
>>>> System.out.println("A * * =>");
>>>> StmtIterator iterator = inf.listStatements(null, null,
>>>> (RDFNode) null);
>>>> while (iterator.hasNext()) {
>>>> System.out.println(" - " + iterator.next());
>>>> }
>>>> }
>>>>
>>>>
>>>> does in fact print "now test" to the console.
>>>>
>>>>
>>>> On 26.01.23 19:43, L B wrote:
>>>>> test1: now(?x) -> print("now test")
>>>>
>>>
>>
>
Re: Builtin primitives in rule not triggered
Posted by L B <da...@gmail.com>.
The current implementation only matches the triples when facts are
updated. Do we have any plan to support built-in primitives?
such as the rule below, the rule will be evaluated when uri1 or uri2 is
updated.
[rule1:
built-inName1(uri1, built-inName2(uri2)) -> xxxx
]
Dave Reynolds <da...@gmail.com> 于2023年1月28日周六 04:56写道：
> Once a rule has triggered it will only retrigger if the data changes in
> a way that affects that rule's bindings. So a rule which doesn't match
> anything on the LHS will not normally be retriggered.
>
> The behaviour you are seeing is as expected for the rule system.
>
> If your goal is to do something whenever data changes irrespective of
> what the change is then you either need a rule with a pattern that will
> match any data i.e. (?s ?p ?o) or don't use rules but use graph
> listeners via the GraphEventManager interface.
>
> Dave
>
> On 27/01/2023 21:31, L B wrote:
> > Thanks for the test code.
> >
> > Please correct me if I am wrong. Per the doc of listStatements: Find all
> > the statements matching a pattern.
> >
> > My problem is that when I update the facts, this rule is not be triggered
> > (executed). I assume this rule will be triggered every time when the
> fact
> > is updated.
> >
> > On the other hand, a leading triple can bypass it. For example
> >
> > [test1: (a b ?c) now(?x) -> print(\"now test\") ]. When you update
> triple
> > (a, b, xxx), the rule will be executed.
> >
> > Lorenz Buehmann <bu...@informatik.uni-leipzig.de> 于2023年1月26日周四
> 23:13写道：
> >
> >> I cannot reproduce this. For example, the test code
> >>
> >>
> >> public static void main(String[] args) {
> >> String raw = "<http://ex.org/a> <http://ex.org/p>
> >> <http://ex.org/b> .";
> >> Model rawData = ModelFactory.createDefaultModel();
> >> rawData.read(new StringReader(raw), null, "N-Triples");
> >> String rules =
> >> "[test1: now(?x) -> print(\"now test\") ]";
> >> Reasoner reasoner = new
> >> GenericRuleReasoner(Rule.parseRules(rules));
> >> InfModel inf = ModelFactory.createInfModel(reasoner, rawData);
> >> System.out.println("A * * =>");
> >> StmtIterator iterator = inf.listStatements(null, null,
> >> (RDFNode) null);
> >> while (iterator.hasNext()) {
> >> System.out.println(" - " + iterator.next());
> >> }
> >> }
> >>
> >>
> >> does in fact print "now test" to the console.
> >>
> >>
> >> On 26.01.23 19:43, L B wrote:
> >>> test1: now(?x) -> print("now test")
> >>
> >
>
Re: Builtin primitives in rule not triggered
Posted by Dave Reynolds <da...@gmail.com>.
Once a rule has triggered it will only retrigger if the data changes in
a way that affects that rule's bindings. So a rule which doesn't match
anything on the LHS will not normally be retriggered.
The behaviour you are seeing is as expected for the rule system.
If your goal is to do something whenever data changes irrespective of
what the change is then you either need a rule with a pattern that will
match any data i.e. (?s ?p ?o) or don't use rules but use graph
listeners via the GraphEventManager interface.
Dave
On 27/01/2023 21:31, L B wrote:
> Thanks for the test code.
>
> Please correct me if I am wrong. Per the doc of listStatements: Find all
> the statements matching a pattern.
>
> My problem is that when I update the facts, this rule is not be triggered
> (executed). I assume this rule will be triggered every time when the fact
> is updated.
>
> On the other hand, a leading triple can bypass it. For example
>
> [test1: (a b ?c) now(?x) -> print(\"now test\") ]. When you update triple
> (a, b, xxx), the rule will be executed.
>
> Lorenz Buehmann <bu...@informatik.uni-leipzig.de> 于2023年1月26日周四 23:13写道：
>
>> I cannot reproduce this. For example, the test code
>>
>>
>> public static void main(String[] args) {
>> String raw = "<http://ex.org/a> <http://ex.org/p>
>> <http://ex.org/b> .";
>> Model rawData = ModelFactory.createDefaultModel();
>> rawData.read(new StringReader(raw), null, "N-Triples");
>> String rules =
>> "[test1: now(?x) -> print(\"now test\") ]";
>> Reasoner reasoner = new
>> GenericRuleReasoner(Rule.parseRules(rules));
>> InfModel inf = ModelFactory.createInfModel(reasoner, rawData);
>> System.out.println("A * * =>");
>> StmtIterator iterator = inf.listStatements(null, null,
>> (RDFNode) null);
>> while (iterator.hasNext()) {
>> System.out.println(" - " + iterator.next());
>> }
>> }
>>
>>
>> does in fact print "now test" to the console.
>>
>>
>> On 26.01.23 19:43, L B wrote:
>>> test1: now(?x) -> print("now test")
>>
>
Re: Re: Builtin primitives in rule not triggered
Posted by L B <da...@gmail.com>.
Thanks for the test code.
Please correct me if I am wrong. Per the doc of listStatements: Find all
the statements matching a pattern.
My problem is that when I update the facts, this rule is not be triggered
(executed). I assume this rule will be triggered every time when the fact
is updated.
On the other hand, a leading triple can bypass it. For example
[test1: (a b ?c) now(?x) -> print(\"now test\") ]. When you update triple
(a, b, xxx), the rule will be executed.
Lorenz Buehmann <bu...@informatik.uni-leipzig.de> 于2023年1月26日周四 23:13写道：
> I cannot reproduce this. For example, the test code
>
>
> public static void main(String[] args) {
> String raw = "<http://ex.org/a> <http://ex.org/p>
> <http://ex.org/b> .";
> Model rawData = ModelFactory.createDefaultModel();
> rawData.read(new StringReader(raw), null, "N-Triples");
> String rules =
> "[test1: now(?x) -> print(\"now test\") ]";
> Reasoner reasoner = new
> GenericRuleReasoner(Rule.parseRules(rules));
> InfModel inf = ModelFactory.createInfModel(reasoner, rawData);
> System.out.println("A * * =>");
> StmtIterator iterator = inf.listStatements(null, null,
> (RDFNode) null);
> while (iterator.hasNext()) {
> System.out.println(" - " + iterator.next());
> }
> }
>
>
> does in fact print "now test" to the console.
>
>
> On 26.01.23 19:43, L B wrote:
> > test1: now(?x) -> print("now test")
>
Re: Re: Builtin primitives in rule not triggered
Posted by Lorenz Buehmann <bu...@informatik.uni-leipzig.de>.
I cannot reproduce this. For example, the test code
public static void main(String[] args) {
String raw = "<http://ex.org/a> <http://ex.org/p>
<http://ex.org/b> .";
Model rawData = ModelFactory.createDefaultModel();
rawData.read(new StringReader(raw), null, "N-Triples");
String rules =
"[test1: now(?x) -> print(\"now test\") ]";
Reasoner reasoner = new
GenericRuleReasoner(Rule.parseRules(rules));
InfModel inf = ModelFactory.createInfModel(reasoner, rawData);
System.out.println("A * * =>");
StmtIterator iterator = inf.listStatements(null, null,
(RDFNode) null);
while (iterator.hasNext()) {
System.out.println(" - " + iterator.next());
}
}
does in fact print "now test" to the console.
On 26.01.23 19:43, L B wrote:
> test1: now(?x) -> print("now test")
Re: Builtin primitives in rule not triggered
Posted by L B <da...@gmail.com>.
Can anyone advise, is it a bug or the way I am using builtin primitives is
wrong?
L B <da...@gmail.com> 于2023年1月24日周二 11:30写道：
> Per Jena rule syntax and structure, I can use builtin primitives in the
> rule.
>
> *term* := (*node*, *node*, *node*) // triple pattern
> or (*node*, *node*, *functor*) // extended triple pattern
> or builtin(*node*, … *node*) // invoke procedural primitive
>
> I have tried the following built-ins, but none of them could be triggered.
>
> [ test1: makeTemp(?x) -> print("makeTemp test") ]
> [ test1: unbound(?x) -> print("unbound test") ]
> [ test1: bound(?x) -> print("bound test") ]
> [ test1: now(?x) -> print("now test") ]
>
> However, if I added one triple ahead as below. It works.
>
> [ test1: (:User rdf:type ?y) makeTemp(?x) -> print("makeTemp test") ]
>
> Where :User is an individual in the system.
>