Re: [rules-users] Best pattern for getting results OUT of Integration server?
On 07/01/2014, dunnlow <dunnlow(a)yahoo.com> wrote:
I have some confusion about running rules in the Integration Server
(v5.5).
I am sending POJOs to the server from a camel (v2.10) Spring client app.
The client inserts a POJO (via batchexecutioncommand) and the rules change
an attribute on the POJO to return the value to the client.
I know, I know, changing attributes of facts is frowned upon (but when I
started I didn't know any better... I swear).
Where did you get this notion, "changing...frowned upon"? It's a
natural enough operation, and the Command lets you request that the
fact object is returned to sender.
The problem I'm having (surprise) is that updating the fact (to return to
the client app) is causing unwanted activations, no-loops, lock-on-actives
etc etc.
Consider calling setX() without modify/update. The returned object
should show the new values, but the Engine will be "blind" to the
updates (which, apparently, is just what you want).
So, I'm looking into changing this and inserting two string
objects into my command so that the rules only modify those string objects.
My questions:
1) Is that the best (/a good) way to implement this?
No, see below.
2) My big question/misunderstanding: Does the integration server handle
the
batchexecutioncommands in series or is it inserting into the working memory
in parallel (ie. are all executions from the first insert completed before
the next batchexecutioninsert command is evaluated)?
A batch executions command is executed in a sequential way.
For example,
If I have a loop that inserts one POJO (Fact.class) and two POJOs (S.class,
a simple class with one string class variable) can I safely do something
like below (is the engine able to keep Fact1 with its inserted S1 and S2
objects separate from the next S objects that might be inserted immediately
after OR might all Facts and S objects get confused (due to
multi-threading,
parallel operation, etc):
rule "evaluate a Fact POJO"
when
$fact1 : Fact (value > 100, card=="NONE")
$s1 : S ()
$s2 : S (this != $s1)
then
$s1 = "OK"
$s2 = "BLUECARD"
This will most certainly NOT do what I think that you think it does,
and it will even do twice, what it does, which doesn't make it any
better.
end
rule "remove inserted objects so memory doesn't fill up"
salience -1000
when
$completedFact : Fact ()
then
retract ($completedFact)
end
rule "remove inserted objects so memory doesn't fill up"
salience -1000
when
$completedS : S ()
then
retract($completedS)
end
My client will use the resulting s1 and s2 values so I obviously don't want
the returned s1 and s2 values for fact1 to be confused with the s1 and s2
values for fact2.
3) Currently, I need to retract the pojos I insert once the processing is
done(like above) -- kinda ugly.
That's the way it is - provided the session remains active and continues.
Another technique that's recommended for returning results is by means
of a global. (I think this is discussed in the Expert manual.)
-W
Is there a way to implement a "logical"
insert for the integration server or a better way to handle this?
Thanks for any thoughts!
-J
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