Jena rules and min/max operation with xsd:dateTime

[Jauhiainen Matti <Ma...@helen.fi>]

Hi,

I have a problem writing jena rules with min/max built in primitives operating on dateTime literals. I have Jena model which contains resource that have dateTime literals, and what I want to do is compare to dateTime literals from two separate resources and assign the max or min value to another resource. An example:

[rule:
(ex:resource1 ex:timestamp ?a)
(ex:resource2 ex:timestamp ?b)
min(?a, ?b, ?c) ->
(ex:resource3 ex:timestamp ?c)
]

The rule works when a and b are bound to integer literals, but fails when a and b are xsd:dateTime literals. For example this works:
[rule:
min(1, 2, ?c) ->
(ex:resource1 ex:timestamp ?c)
]

while this does not:

[rule:
min('16-05-12T00:00:00'^^xsd:dateTime, '16-05-12T01:00:00'^^xsd:dateTime, ?c) ->
(ex:resource1 ex:timestamp ?c)
]

I am using the GenericRuleReasoner of Jena 2.7.0, this is the code I use for inference:
        String rules = "...";//see above
        Reasoner reasoner = new GenericRuleReasoner(Rule.parseRules(rules));
        InfModel m = ModelFactory.createInfModel(reasoner, model);

greaterThan(), lessThan(), ge() and le() work just fine with the dateTime literals I operate with, but when I try to use min and max with same literals, the rule with min or max fails and nothing get inferred. Is the min and max even supposed to work with dateTime literals or am I doing something silly here?



Regards,

Matti

Re: Jena rules and min/max operation with xsd:dateTime

[Dave Reynolds <da...@gmail.com>]

On 16/05/12 13:32, Jauhiainen Matti wrote:
> Hi,
>
> I have a problem writing jena rules with min/max built in primitives operating on dateTime literals. I have Jena model which contains resource that have dateTime literals, and what I want to do is compare to dateTime literals from two separate resources and assign the max or min value to another resource. An example:
>
> [rule:
> (ex:resource1 ex:timestamp ?a)
> (ex:resource2 ex:timestamp ?b)
> min(?a, ?b, ?c) ->
> (ex:resource3 ex:timestamp ?c)
> ]
>
> The rule works when a and b are bound to integer literals, but fails when a and b are xsd:dateTime literals. For example this works:
> [rule:
> min(1, 2, ?c) ->
> (ex:resource1 ex:timestamp ?c)
> ]
>
> while this does not:
>
> [rule:
> min('16-05-12T00:00:00'^^xsd:dateTime, '16-05-12T01:00:00'^^xsd:dateTime, ?c) ->
> (ex:resource1 ex:timestamp ?c)
> ]
>
> I am using the GenericRuleReasoner of Jena 2.7.0, this is the code I use for inference:
>          String rules = "...";//see above
>          Reasoner reasoner = new GenericRuleReasoner(Rule.parseRules(rules));
>          InfModel m = ModelFactory.createInfModel(reasoner, model);
>
> greaterThan(), lessThan(), ge() and le() work just fine with the dateTime literals I operate with, but when I try to use min and max with same literals, the rule with min or max fails and nothing get inferred. Is the min and max even supposed to work with dateTime literals or am I doing something silly here?

Looks like an omission, dateTime support is missing from the min/max code.

Should be easy to fix but I'm not able to look at it right now so I've 
created a Jira for it.

Dave