/**
  * creates a config item for the sensors polling time
  *
  * @param sensor
  * @return
  */
 private String createSensorPollTimeConf(Sensor sensor) {
   String sensorsPollTimeKey = POLLTIME + sensor.ident;
   String value = m_prefs.getValue(sensorsPollTimeKey);
   Configuration config =
       new Configuration(
           "polling time of sensor " + sensor.description,
           sensorsPollTimeKey,
           SettingType.number,
           value);
   return AdminServerProtocolAbstractor.createSensorConfigMessage(sensor.ident, config);
 }
 /**
  * this creates a config item for the admin clients which allows them to toggle the visibility of
  * a sensor
  *
  * @param sensor the sensor
  */
 private String createSensorVisiblityConf(Sensor sensor) {
   String sensorsVisibilityKey = VISIBILITY + sensor.ident;
   String value = m_prefs.getValue(sensorsVisibilityKey);
   Configuration config =
       new Configuration(
           "visibility of sensor " + sensor.description,
           sensorsVisibilityKey,
           SettingType.bool,
           value);
   return AdminServerProtocolAbstractor.createSensorConfigMessage(sensor.ident, config);
 }