does anybody know if there is a way to do for loops in drools ?.
I am trying to loop through a list of string to see if one of the strings matches a pattern e.g.
def listOfStrings = ['a','a.b','a.b.c']
for(String s:listOfStrings){
if(s matches "^a.b.*$"){
return true
}
}
I have written the following rule based on what documentation I could find, but I dont think the syntax is correct
rule "Matcher"
when
TestClass : TestClass(($s matches "^a.b.*$") from listOfStrings, count($s))
then
TestClass.setResponse( "Condition is True !!" );
end
I am finding it hard to find good documentation on the drl language
I would appreciate any help that anybody can give me
Based on the previous answer, I have tried the following
rule "Matcher"
when
TestClass:TestClass(String( this matches "^a.b.*$" ) from listOfStrings)
then
TestClass.setResponse( "Condition is True !!" );
end
However, I now get the following error message:
[43,197]: unknown:43:197 Unexpected token 'this'
Answer
I think you've misunderstood the fundamentals of a rules engine; you need to think a bit differently.
Instead of 'iterating' over the list, you need to break the list into its component strings and insert them individually as facts into working memory.
Only the strings/facts which match the 'when' condition will fire the rule.
You might also want to look into globals and queries. global will allow you to inject a service into your working memory for your consequences to call, and the query might be a way by which you can obtain the matched strings out of working memory.