code: public Enumeration listMessagingEngines() {
  
          String thisMethodName = CLASS_NAME + ".listMessagingEngines()";
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.entry(tc, thisMethodName, this);
          }
  
          Vector v = new Vector();
  
          Enumeration vEnum = _messagingEngines.elements();
          while (vEnum.hasMoreElements()) {
              Object o = vEnum.nextElement();
              Object c = ((MessagingEngine) o).getRuntime();
              if (c instanceof BaseMessagingEngineImpl)
                  v.addElement(c);
          }
  
          Enumeration elements = v.elements();
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.exit(tc, thisMethodName);
          }
  
          return elements;
      }
docs: Return a list of Messaging Engines
  
  @return Enumeration