/**
  * Adds a feature to the ThreadGroup attribute of the RemoteJMeterEngineImpl object.
  *
  * @param testTree the feature to be added to the ThreadGroup attribute
  */
 @Override
 public void rconfigure(HashTree testTree, String host, File jmxBase, String scriptName)
     throws RemoteException {
   log.info("Creating JMeter engine on host " + host + " base '" + jmxBase + "'");
   synchronized (LOCK) { // close window where another remote client might jump in
     if (backingEngine != null && backingEngine.isActive()) {
       log.warn("Engine is busy - cannot create JMeter engine");
       throw new IllegalStateException("Engine is busy - please try later");
     }
     ownerThread = Thread.currentThread();
     backingEngine = new StandardJMeterEngine(host);
     backingEngine.configure(testTree); // sets active = true
   }
   FileServer.getFileServer().setScriptName(scriptName);
   FileServer.getFileServer().setBase(jmxBase);
 }