[rules-users] form of accumulate in examples is depricated?

[Wolfgang Laun]

You must have misinterpreted the Expert manual.

At #d0e6921, which you quote, it says that "Accumulate with inline custom code
is not a good practice for several reasons". So we have

1) from accumulate (as used in the Planner example)
2) Inline custom code
3) Java implementation

But there is a fourth way, see 4.8.3.7.4.1., Accumulate CE (preferred syntax)

 This is the Planner example, rewritten:

 $computer : CloudComputer($cpuPower : cpuPower)
 accumulate(  CloudProcess(
                 computer == $computer,
                 $requiredCpuPower : requiredCpuPower);
            $requiredCpuPowerTotal :  sum($requiredCpuPower),
            $requiredCpuPowerTotal  > $cpuPower )

-W

On 22/01/2013, Michiel Vermandel <mvermand at yahoo.com> wrote:
> Hi,
>
> In lots of rules in the drools planner examples the accumulate function is
> used in this way:
>
> rule "requiredCpuPowerTotal"
>     when
>         $computer : CloudComputer($cpuPower : cpuPower)
>         $requiredCpuPowerTotal : Number(intValue > $cpuPower) from
> accumulate(
>             CloudProcess(
>                 computer == $computer,
>                 $requiredCpuPower : requiredCpuPower),
>             sum($requiredCpuPower)
>         )
>     then
>         insertLogical(new IntConstraintOccurrence("requiredCpuPowerTotal",
> ConstraintType.NEGATIVE_HARD,
>                 $requiredCpuPowerTotal.intValue() - $cpuPower,
>                 $computer));
> end
>
> (example from cloudBalancing).
>
> Though, documentation says
> (http://docs.jboss.org/drools/release/5.5.0.Final/drools-expert-docs/html_single/#d0e6921)
> one should this syntax:
>
> <result pattern> from accumulate( <source pattern>,
>                                   init( <init code> ),
>                                   action( <action code> ),
>                                   reverse( <reverse code> ),
>                                   result( <result expression> ) )
>
> Does this mean that the axemples could be optimized and that I should go for
> that syntaxt as well rather than using the syntax like rule
> "requiredCpuPowerTotal" ?
>
> Thanks
>
>
>
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