code: @Override
      public String[] getDeviceList(final String serverName, final String className) throws DevFailed {
          return cache.getDeviceList(serverName, className);
      }
docs: Get the list of device for a server and a class (execute DbGetDeviceList on DB device)
  
  @param serverName
  The server name
  @param className
  The class name
  @return
  @throws DevFailed