are for loops possible in drools ?

Question

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

Answer 1

The Rete algorithm doesn't work this way.

I think you want to try regex in Drools.

Answer 2

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 3

I got around this issue by converting my list to a string and checking to see if it matches the regex