Re: [rules-users] Alternative for using a regular expression
Hi Dean,
Is the encoded value used elsewhere within your organisation from the same
object model?
It'd make a compelling reason to suggest your model is enriched to expose
the decoded flags if they are (e.g. reporting).
However all is not lost:-
(1) You can use "matches" regular expressions (as you identified):-
rule "one"
when
$c : Claim( claimStatus matches ^.{4}1324.{0,} )
then
//Something
end
(2) You can use "eval":-
rule "two"
when
Claim( $cs : claimStatus )
eval($cs.substring(3, 7).equals("1234"))
then
//Something
end
(3) You can use "from" and a global helper class:-
global MyDecoder myDecoder
rule "three"
when
Claim( $cs : claimStatus )
String( toString == "1234" ) from myDecoder.decodeClaimStatus($cs)
then
//Something
end
See attached example project for the last option.
You could then use DSL to "hide" the technical implementations for your
users.
With kind regards,
Mike
2010/10/20 Dean Whisnant <dean(a)basys.com>
Hello,
In designing our rules system to allow users and analysts to create and
edit rules (through Guvnor) we have a requirement that some of the fields be
able to be evaluated for specific characters in specific positions of the
string. See the following examples:
Example 1: The string named “claimStatus” contains various flags all pushed
together in a string. It might look like “ABS1324BB7”. Together this field
means about nothing, but position 4-7 (1324) is an important code that they
want to evaluate. A business rule for this would be if position 4-7 in
claimStatus = “1324” then we categorize that claims for some reason.
In loose java syntax I would likely use ‘if claimStatus.substring(3,4) =
“1324” then do something.
I could have the user program a formula using the substring method, but
that would be quite inefficient and a lot of information for them to figure
out.
I could have the user say claimStatus matches ^.{4}1324.{0,} but this
regular expression is quite cryptic.
While at Rulesfest I ran the topic by a couple folks there and they thought
that posing it to the community might be a good idea. Is there another way
you could see doing this? Is there a DSL format that might get us to where
we want?
Ideas that have been thought of included creating a variable that is
already just the 4 characters we are after, but there are dozens of fields
that could hold this info and that would increase our data model which is
already quite verbose. We also looked at allowing them to create a variable
when they need it and then just reuse that in rules, but I’m not certain how
we would do this with as many fields.
To add to it, the regular expression I listed is for one of the fields in
these streams, we also have needs to pull out other positions as well.
Your thoughts and ideas on this are appreciated.
Thank you!
Dean Whisnant
basys, inc.
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