[rules-users] Globals asserted as facts... how to modify them...

[Marcus Ilgner]

Hi,

On Feb 16, 2008 1:00 PM, mmquelo massi <mmquelo at gmail.com> wrote:
>
> Hi everybody,
>
> I followed all the topics about globals and the fact that they are
> immutables.
>
> I also understood that once we decide to reason over globals, it's
> time we no more use them and we start to use simple WM facts.
>
> Now...
>
> I tell you my scenario.
>
> I have got two globals.
>
> A "request" global and a "reply" global. The first one is a "Request" java
> instance
> and the second one is a "Reply" java instance. They belong to the Object
> model
> I designed.
>
> My application makes a request to the rule engine passing it a "request" as
> global,
> and get back a reply from it receiving a modified "reply"  global.
>
> I use a ruleflow to execute the rules.
>
> I think everything would be perfect and smooth if I had not the need to
> reason
> over the reply during the rule session....
>
> That's the point!
>
> I do not just need to modify the "reply" global in order to get the final
> value outside
> the rule engine, but I DO need to reason over it INSIDE the rule session.
>
> So.... what should I do in order to reason over the reply INSIDE AND OUTSIDE
> the Rule Session?
>
> Should I insert the "reply" global into the WM?
>
> Let assume I do that, what happen if I pass the "reply" global to
> a drools function which alters the "reply"?
>
> Imagine a rule as follows and imagine I previously inserted the "reply"
> global into the WM:
>
> ----
> ...
> global my.object.model.Reply reply
> ...
> rule "addcriminal_2_reply"
>   when
>     $p: Person(job=="criminal")
>   then
>      addCriminaltoReply(reply, $p );
> end
> ----
>
> Will this alteration affect the corresponding Reply() fact in the WM as
> well?
>
>
> Now let see this other rule:
>
> (Same, let imagine i previously inserted: insert(reply); )
> ----
> global my.object.model.Reply reply
>
>
> rule "FullFill_replyCode"
>   when
>      $r: Reply(code=="john.wayne") from reply
>   then
>      $r.code.name = john;
>      $r.code.lastname = wayne;
> end
> ----
>
> If I execute this rule in a ruleflow, do i need to "update($r)"
> in order to get the modified $r value in the next ruleflow node?
>
> And what happens to the global??? Will it get modified as well?
>
> I am sure you can help me.
>
> Bye bye.
>
> Massi
>

have you thought about initializing and asserting the Reply instance
in a separate rule at the beginning of the ruleflow?
After the ruleflow has finished, you can look for instances of Reply
in the WorkingMemory and retrieve your Reply object.

Best regards
Marcus