* @return a reference to enable cascade calls.
* @throws UPInvalidParameterException if the description is invalid.
*/
protected final UPOutput setOutputDescription(final String outputDescription) throws UPInvalidParameterException {
if (outputDescription==null) {
throw new UPInvalidParameterException("Output description can not be null");
} else if (outputDescription.isEmpty()) {
this.outputDescription = "No description supplied";
} else {
this.outputDescription = outputDescription;
}