drl file looks like this.. global ArrayList<Long> accountNumberBlackList . . . rule blackListToCheck when "$transaction : Transaction(accountTo.number in (accountNumberBlackList))" then $transaction.setStatus(Transaction.Status.DENIED); //.. do something else? end I want to use 'in' operator to find numbers that are stored in global variable accountNumberBlackList. Is the above syntax(in double quotes) correct? is there any alternative to look inside a list?