public Duration evaluateAsDuration(OExpression cexp,
EvaluationContext context) throws FaultException, EvaluationException {
String literal = this.evaluateAsString(cexp, context);
try {
return new Duration(literal);
} catch (Exception ex) {
String errmsg = "Invalid duration: " + literal;
__log.error(errmsg, ex);
throw new FaultException(cexp.getOwner().constants.qnInvalidExpressionValue,
errmsg);