[rules-users] question on rule efficiency

[Edson Tirelli]

   Barry,

   For your example, there would be no difference really, because Drools
detects that "putContract" is a pattern binding and that "strikePrice" is a
field of "putContract". So, in your version number, it will automatically
generate a binding for the field and behind the scenes, it will behave
exactly like version 2.
   Although, it is IMPORTANT to note that, if "putContract" was not a
pattern binding (for instance, it could be a field binding itself) or if you
had used deeper nested accessors, like "person.address.street", drools would
not be able to optimize and it would be more expensive to execute.

   []s
   Edson

2008/6/5 Barry Kaplan <groups1 at memelet.com>:

>
> When the value of a property is compared across two instances, is it better
> to create variables for the properties, or is using the object.property for
> the comparison equivalent?
>
> Here's an example: I need to match based on the strikePrice property. Is
> either version better than the other?
>
>
> version 1)
>
>   putContract  : OptionInstrument(
>                                   optionType == OptionType.PUT)
>   callContract : OptionInstrument(
>                                   optionType == OptionType.CALL,
>                                   strikePrice > putContract.strikePrice)
> // compare using navigation
>
> version 2)
>   putContract  : OptionInstrument(
>                                   optionType == OptionType.PUT,
>                                   putStrikePrice : strikePrice)
> // delcare the variable
>   callContract : OptionInstrument(
>                                   optionType == OptionType.CALL,
>                                   strikePrice > putStrikePrice)
> // compare using variable
>
> --
> View this message in context:
> http://www.nabble.com/question-on-rule-efficiency-tp17672843p17672843.html
> Sent from the drools - user mailing list archive at Nabble.com.
>
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-- 
Edson Tirelli
JBoss Drools Core Development
Office: +55 11 3529-6000
Mobile: +55 11 9287-5646
JBoss, a division of Red Hat @ www.jboss.com
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