[jboss-jira] [JBoss JIRA] (DROOLS-314) Build in accumulate functions are highly unreliable for long's and BigDecimals

Build in accumulate functions are highly unreliable for long's and BigDecimals ------------------------------------------------------------------------------ Key: DROOLS-314 URL: https://issues.jboss.org/browse/DROOLS-314 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Reporter: Geoffrey De Smet Assignee: Edson Tirelli Priority: Critical Attachments: JBRULES-1322-testcase.patch When dealing with financial data, one should never ever use double's. Instead BigDecimal should be used. Not because BigDecimal is bigger (that's rarely a problem) but because it doesn't do any decimal to binary transformation. For example, it's impossible for a double to correctly represent "0.2", aka 1/5. Summing many doubles (or even a few differing in scale), can easily give wrong results (and for financial data this tends to be important). Using doubles to sum longs have the exact same problem. Attached is a testcase patch which proves this by checking if (MAX_LONG - 4L) and 3L sum up to be (MAX_LONG - 1L). Currently they don't. One possible way to solve this is to fix JBRULES-1075, which just happens to give drools-solver 3% more performance ;) what a coincidence ^^