code: public List<Notification> getByInteraction(String interaction) {
          List<Notification> found = new ArrayList<Notification>();
          for (Notification n: NotificationManager.notifications)
              if (((InteractionNotification)n).getInteraction().equals(interaction)){ 
                  logger.fine("...found a match for getByInteraction query. With interaction: " +
                              interaction);
                  found.add(n);
              }
          if(found.size()>0)        
              return found;
          return null;
      }
docs: Search for notifications of interaction type that match the given class name.
  
  @param interaction
  the class that defines the interaction type of desired notifications.
  @return
  a List with the notifications founded that match the given class name.