code: public Database set_db_obj(final String tango_host) throws DevFailed {
  	final int i = tango_host.indexOf(":");
  	if (i <= 0) {
  	    Except.throw_connection_failed("TangoApi_TANGO_HOST_NOT_SET",
  		    "Cannot parse port number", "ApiUtil.set_db_obj()");
  	}
  	return change_db_obj(tango_host.substring(0, i), tango_host.substring(i + 1));
      }
docs: ===================================================================