[rules-users] question on drools and method calls on facts

[Wolfgang Laun]

It depends whether you are a purist, a pragmatist, or a maverick. A few
random thoughts, and note that I consider myself a repenting pragmatist ;-)

Having fact classes with methods that modify the object in addition to the
usual setters is dangerous; a toString() according to the convention is
harmless.

Even from a purist's point of view your list could be extended by "calls of
methods to global objects", e.g., for communicating results to some GUI or
whatever.

What is usually frowned at it the use of conditional statements on the RHS
as going against the spirit of rule based programming.

If complex processing is required, hide it in some static methods of an
utility class. It will make your rule code trimmer and slimmer, avoiding
needless binding between the business logic part and implementation details.

-W


On Tue, Sep 1, 2009 at 11:02 PM, Garner, Shawn
<Garner.Shawn at principal.com>wrote:

> I'm under the impression that in the action clause of a rule you should
> only do one of the following:
> 1) Set a property on a Fact
> 2) Retract a Fact
> 3) Insert (Assert) a new Fact
> 4) Modify an existing Fact
>
> However in some of the examples in the documentation it shows calling
> methods other than bean property getters and setters.
> I was wondering if what other peoples opinions are on whether you should be
> doing more than the 4 things I listed above in a then clause of a rule.
>
> Thanks,
> SG
>
>
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