9:38 p.m.
Hi All,
I am seeking some kind of filtering (if statement) inside the LHS.
I have the following example rule (note: $attributeFilteredSentences and
$cmdescriptor are defined in the extends rule which is not presented):
rule " choose message sentence example" extends "
attributeFilteredSentences
collection"
when
SContextState(state == SContextState.ONE)
$sentences: ArrayList()
from collect (Sentences.Sentence(
descriptor.meanings.meaning == $cmdescriptor.meanings.meaning
) from
$attributeFilteredSentences)
then
logger.info("RULE: entered rule: "+drools.getRule().getName());
//some logic.
end
as can be seen I am filtering sentences based on the meanings, and the
meaning collection must be identical as in $cmdescriptor (this is the case
when SContextState.ONE)
Now to my question: I have cases ((this is the case when SContextState.TWO)
where I do not need exact validation but rather superset of (for this I have
a supersetOf operator implemented)
I would like to avoid duplicating this rule (as I have similar condition in
many other rules) and being able to filter once with "==" and once with
"supersetOf" depending on the SContextState.
Any ideas how to do this?
Thanks,
Hezi
12:30 a.m.
On 23/02/2012 03:38, Hezi Stern wrote:
Hi All,
I am seeking some kind of filtering (if statement) inside the LHS.
I have the following example rule (note: $attributeFilteredSentences
and $cmdescriptor are defined in the extends rule which is not presented):
*rule*" choose message sentence example"extends "
attributeFilteredSentences collection"
*when*
SContextState(state == SContextState.ONE)
$sentences: ArrayList()
*from**collect*(Sentences.Sentence(
descriptor.meanings.meaning == $cmdescriptor.meanings.meaning
)
*from* $attributeFilteredSentences)
*then*
logger.info("RULE: entered rule:
"+drools.getRule().getName());
//some logic...
*end*
**
as can be seen I am filtering sentences based on the meanings, and the
meaning collection must be identical as in $cmdescriptor (this is the
case when SContextState.ONE)
Now to my question: I have cases ((this is the case when
SContextState.TWO) where I do not need exact validation but rather
superset of (for this I have a supersetOf operator implemented)
I would like to avoid duplicating this rule (as I have similar
condition in many other rules) and being able to filter once with "=="
and once with "supersetOf" depending on the SContextState.
I have found that query's can be used to provide re-usable rule
fragments. In the example below I could have inlined the intentory LHS
in the updateInventory rule, but instead I separated it out into a query
so that multiple rules can re-use it. There is a small performance
overhead from using queries, compared to normal patterns, but in most
cases this is compensated by more maintainable and readable code.
query inventory(Character $char, List $inventory)
$char := Character()
$inventory := List() from accumulate( Holding( $char, $thing; ),
collectList( $thing ) )
end
rule updateInventory salience 5 when
SessionCharacter( $char : character, $us : session )
inventory( $char, $things; )
then
$us.channels["inventory"].send( $things );
end
Mark
Any ideas how to do this?
Thanks,
Hezi
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rules-users(a)lists.jboss.org
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2:01 a.m.
Using queries doesn't solve the Hezi's problem which is the selection
of an operator based on some property value.
Relying on Java and evel, you can always write an expression such as
eval( $ctxt.state == SContextState.ONE ?
$ds.sentence.equals( $someSentence ) :
$ds.sentence.memberOf( $sentenceSet ) )
(Sorry, I did not try to stick to your complex class structures.)
-W
On 23/02/2012, Mark Proctor <mproctor(a)codehaus.org> wrote:
On 23/02/2012 03:38, Hezi Stern wrote:
>
> Hi All,
>
> I am seeking some kind of filtering (if statement) inside the LHS.
>
> I have the following example rule (note: $attributeFilteredSentences
> and $cmdescriptor are defined in the extends rule which is not presented):
>
> *rule*" choose message sentence example"extends "
> attributeFilteredSentences collection"
>
> *when*
>
> SContextState(state == SContextState.ONE)
>
> $sentences: ArrayList()
>
> *from**collect*(Sentences.Sentence(
>
>
> descriptor.meanings.meaning == $cmdescriptor.meanings.meaning
>
> )
> *from* $attributeFilteredSentences)
>
> *then*
>
> logger.info("RULE: entered rule:
> "+drools.getRule().getName());
>
> //some logic...
>
> *end*
>
> **
>
> as can be seen I am filtering sentences based on the meanings, and the
> meaning collection must be identical as in $cmdescriptor (this is the
> case when SContextState.ONE)
>
> Now to my question: I have cases ((this is the case when
> SContextState.TWO) where I do not need exact validation but rather
> superset of (for this I have a supersetOf operator implemented)
>
> I would like to avoid duplicating this rule (as I have similar
> condition in many other rules) and being able to filter once with "=="
> and once with "supersetOf" depending on the SContextState.
>
I have found that query's can be used to provide re-usable rule
fragments. In the example below I could have inlined the intentory LHS
in the updateInventory rule, but instead I separated it out into a query
so that multiple rules can re-use it. There is a small performance
overhead from using queries, compared to normal patterns, but in most
cases this is compensated by more maintainable and readable code.
query inventory(Character $char, List $inventory)
$char := Character()
$inventory := List() from accumulate( Holding( $char, $thing; ),
collectList( $thing ) )
end
rule updateInventory salience 5 when
SessionCharacter( $char : character, $us : session )
inventory( $char, $things; )
then
$us.channels["inventory"].send( $things );
end
Mark
>
> Any ideas how to do this?
>
> Thanks,
>
> Hezi
>
>
>
> _______________________________________________
> rules-users mailing list
> rules-users(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
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2 comments
3 participants
participants (3)
-
Hezi Stern -
Mark Proctor -
Wolfgang Laun