if( contributors.isEmpty() )
{
String contributor = validationContext.getProperty(HttpHeaders.X_ON_BEHALF_OF);
if( contributor != null )
{
result.addValidationInfo(new SwordValidationInfo(Contributor.elementName(),
SwordValidationInfo.MISSING_ELEMENT_ERROR +
" This item SHOULD contain the value of the X-On-Behalf-Of header, if one was present in the POST request.",
SwordValidationInfoType.ERROR));
}
}