/**
  * DOC ggu Comment method "getDisplayText".
  *
  * <p>mainly for label provider of update manager dialog.
  *
  * @param element
  * @param columnIndex
  * @return
  */
 public String getDisplayText(Object element, int columnIndex) {
   IProcessUpdateManagerProvider[] processProviders = reader.getProcessProviders();
   for (IProcessUpdateManagerProvider provider : processProviders) {
     String displayText = provider.getDisplayText(element, columnIndex);
     if (displayText != null) {
       return displayText;
     }
   }
   return null;
 }