private final class SingleDigitValidator implements IValidator
        {
            public IStatus validate(Object value)
            {
                Integer i = (Integer) value;
                if (i == null)
                {
                    return ValidationStatus.error("Please enter a value.");
                }
                if (i.intValue() < 0 || i.intValue() > 9)
                {
                    return ValidationStatus.error("Value must be between 0 and 9.");
                }
                return ValidationStatus.ok();
            }
        }