2010/10/7 Dean Whisnant <dean(a)basys.com>
I’ve only been working with Drools for a little over a month or so now and
I’ve begun integrating it into my application via Eclipse and creating DRL
files. The nature of this application is to take a data record from one
file and create a new data record in another file. This is done in a batch
of any number of records, depending on the number of records sent to us in
the first file. To accomplish this I have two classes, one representing each
file, and I create and object for each of them, inserting them into the
knowledge session and then fire the rule.
The first object has around 1,000 fields and the second has 250, so my
class structure is quite broad.
In a DRL file I have created the following rule:
*rule* "Primary Diagnosis Code"
$ccl : anObjectIn(IncomingDiag1 != *null*)
$cdl : anObjectOut()
$cdl.PrimaryDiag = $ccl.IncomingDiag1;
This rule fires great and the PrimaryDiag field in myObjectOut is updated
with what iss in myObjectIn.IncomingDiag. I can then write the object
back out the the database fine.
A requirement of my project is that I allow users (analysts) to create
their own rules that are above and beyond those I might create in a .drl
file. To do so we are looking to deploy Guvnor and let them use the Guided
editor to create rules. I’ve already loaded my fact models into Guvnor and
have them available in the drop down conditions.
The questions that are hitting me now are:
1) On the LHS when I’ve chosen the fiels IncomingDiag the only
options I have for conditions are “equal to”, “not equal to”, “matches”, and
“sounds like”. I don’t see an option for null or notnull. If I were to
choose “not equal to” I then have the options for Literal Values, New
Formulas, or Expression Editor (which has none by default). I haven’t seen
any examples where someone is evaluating a field in Guvnor for being either
“” or null. How would one accomplish this? The literal value does not
allow you to leave it blank as in “” and if you type “” in it, the
source shows “”””.
2) On the LHS, if I were to want to evaluate IncomingDiag1 ==
IncomingDiag2 I don’t see a method except if I were to choose New Formula
and type in the field name Incoming Diag2. Is there another way that they
could be prompted for the field choises again?
If you create a bound variable, then you will see when you select the value
of the operateor a "bound variable" button. So that then you can select the
3) On the RHS, when I go to add a new then, I’m prompted to
only to either “insert fact anObjectIn” or to “logically insert fact
anObjectIn” or to manually enter DRL logic. Both of the inserts appear to
create logic that would create a new object with the data in it:
anObjectIn fact0 = new anObjectIn ();
fact0. IncomingDiag1 ( 11 );
But what I really want is something similar to my DRL from above.
Am I missing something? Or would this have to be a case where they would
manually enter the DRL statement?
Senior Software Developer
rules-users mailing list