Re: [rules-users] How does 'from' cache works?
On 12/09/2012, Esteban Aliverti <esteban.aliverti(a)gmail.com> wrote:
Assuming I have the following rule:
global SomeClient client;
rule "Poll Values"
timer (int: 0s 1s)
when
$data: Data() from client.getData();
then
insert($data);
end
and that I'm just creating a session with just that rule, setting the
global and calling fireAllRules(). And let's say that my session is running
for 5 seconds.
My questions are:
1.- How many times is the rule going to be executed?
This depends on the condition remaining true after its initial and
only evaluation.
2.- How many times is client.getData() going to be invoked?
Once: client never changes, or art least there is no way to inform the
Engine about a change. "from" followed by something in a fact would be
different.
The test I have shows that the rule is executed 5 times,
but client.getData() is only invoked for the first activation. The returned
object is used in the subsequent activations. Is this the expected
behavior?
Yes.
As the rule name states, I'm expecting to get some (different)
values from
client every second.
I understand that I'm doing 'strange' things since the rule doesn't use
any
real fact but I would like to understand why I'm experiencing the described
behavior.
I hope it's clear now.
-W
Best Regards,
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Esteban Aliverti
- Blog @ http://ilesteban.wordpress.com