How to use

astEvent

method

in

org.kie.dmn.feel.lang.ast.SignedUnaryNode

@Override
public Object evaluate(EvaluationContext ctx) {
  if (expression == null) return null;
  BigDecimal result = EvalHelper.getBigDecimalOrNull( expression.evaluate( ctx ) );
  if ( result == null ) {
    ctx.notifyEvt( astEvent(Severity.WARN, Msg.createMessage(Msg.NEGATING_A_NULL)));
    return null;
  } else if ( Sign.NEGATIVE == sign ) {
    return BigDecimal.valueOf( -1 ).multiply( result );
  } else {
    return result;
  }
}