code: @Override
      public void serviceChanged(ServiceEvent event) {
          ServiceReference<?> ref = event.getServiceReference();
          switch (event.getType()) {
              case ServiceEvent.REGISTERED:
                  recordEntry(ref);
                  break;
              case ServiceEvent.MODIFIED:
                  moveEntry(ref);
                  break;
              case ServiceEvent.MODIFIED_ENDMATCH:
              case ServiceEvent.UNREGISTERING:
                  removeEntry(ref);
                  break;
              default:
                  break;
          }
      }
docs: {@inheritDoc}