Hi, guys:
I am using Drools 4.0.7. I find a strange behavior. When my LHS is "Message( varDouble == 99.9 )" and "varDouble" equals "new Double(99.9)", the condition is true. But when my LHS is "Message( types.doubleType == 99.9 )" and the "doubleType" field is also equal to "new Double(99.9)", the condition is false. I debug the code, and find that:
When the LHS is "Message( varDouble == 99.9 )", the logic will handle the literal 99.9 as Double.valueOf( “99.9” ), and the comparison is between (new Double(99.9)).doubleValue() and Double.valueOf( “99.9” ).doubleValue(),
When the LHS is "Message( types.doubleType == 99.9 )", the logic is different from above. The comparison is between new BigDecimal((Double) 99.9, MathContext.DECIMAL64) (which double value is 99.90000000000001) and new BigDecimal(“99.9”, MathContext.DECIMAL64) (which double value is 99.9).
I think we need make things consistent. "varDouble" and "types.doubleType" are of the same type and value. It doesn't make sense to have different behavior just because of one field is nesting while the other is not. I know Drools is using MVEL to evaluate the condition. But I am not sure it is a MVEL bug or Drools uses MVEL wrong. It will be much appreciated if you can give me any comments!