code: public void addMediaListener(JingleMediaListener li) {
          for (ContentNegotiator contentNegotiator : contentNegotiators) {
              if (contentNegotiator.getMediaNegotiator() != null) {
                  contentNegotiator.getMediaNegotiator().addListener(li);
              }
          }
  
      }
docs: Add a listener for jmf negotiation events.
  
  @param li
  The listener