code: public static JsMessagingEngine[] getMessagingEngines(final String busName) {
  
          final String methodName = "getMessagingEngines";
          if (TRACE.isEntryEnabled()) {
              SibTr.entry(TRACE, methodName, busName);
          }
  
          final JsMessagingEngine[] result;
  
          synchronized (MESSAGING_ENGINES) {
  
              // Do we have any messaging engines for the given bus?
              final Set messagingEngines = (Set) MESSAGING_ENGINES.get(busName);
  
              if (messagingEngines == null) {
  
                  // If not, return an empty array
                  result = new JsMessagingEngine[0];
  
              } else {
  
                  // If we do, convert the set to an array
                  result = (JsMessagingEngine[]) messagingEngines
                          .toArray(new JsMessagingEngine[messagingEngines.size()]);
  
              }
  
          }
  
          if (TRACE.isEntryEnabled()) {
              SibTr.exit(TRACE, methodName, result);
          }
          return result;
  
      }
docs: Returns an array of initialized messaging engines for the given bus. If
  there are none, an empty array is returned.
  
  @param busName
  the bus name
  @return the set of <code>JsMessagingEngine</code> instances