Heating and window contact - a (simple?) rule [SOLVED]

[Max77 (Max)]

Hi all,

I am starting to implement rules to trigger heating on/off when a window will be closed/opened.

The window contact (ESP8266 based, self designed/programmed ) works through MQTT protocol

Switch  Studio_Window_StudWinESP8266reed_DoorSensor   "Studio Window Status [MAP(reed.map):%s]"   <door>        (GuestRoom, gOpenItems)   ["ReedSensor"]      {channel="mqtt:homie300:efd6615c:studwinesp8266reed:studWinESP8266reed#doorSensor"}

with reed.map

OFF=closed
ON=open
NULL=unknown

The corresponding thermovalve (Spirit Z-wave) has an item to control the heat mode

Number Studio_ZWaveThermoValve_ThermostatMode "Guest Room Thermovalve Mode [%.1f]"                    <temperature>      (GuestRoom, gThermoValveMode)    ["Thermovalve Mode"]   {channel="zwave:device:f3ae20de:node2:thermostat_mode"}

Both the status of the door sensor and the manual setting of the thermovalve work perfectly.

Now the rule (far from being elegant, but I want a first working set before going for bells and whistles - suggestions welcome!)

rule "A door sensor has been triggered"
when
    Member of gOpenItems changed
then
    val String ruleIdentifier = "Setting Thermovalve"

    val window = triggeringItem

    logInfo(ruleIdentifier, "{} has triggered the event!", window.name)

    val roomName = window.name.split("_").get(0)
    val thermoValveName = roomName+"_ZWaveThermoValve_ThermostatMode"

    val windowState = if(window.state == ON) "open" else "close"
    val setValue = if(window.state == ON) 0 else 1

    logInfo(ruleIdentifier, "{} has just {}! Setting {} to {}", roomName, windowState, thermoValveName, setValue)

    thermoValveName.sendCommand(setValue)
end

The rule does not work, and the error message is

2020-03-20 23:46:32.737 [INFO ] [ome.model.script.Setting Thermovalve] - Studio_Window_StudWinESP8266reed_DoorSensor has triggered the event!
2020-03-20 23:46:32.750 [INFO ] [ome.model.script.Setting Thermovalve] - Studio has just open! Setting Studio_ZWaveThermoValve_ThermostatMode to 0
2020-03-20 23:46:32.753 [ERROR] [ntime.internal.engine.RuleEngineImpl] - Rule 'A door sensor has been triggered': An error occurred during the script execution: Could not invoke method: org.eclipse.smarthome.model.script.actions.BusEvent.sendCommand(java.lang.String,java.lang.String) on instance: null

If I replace the line

thermoValveName.sendCommand(setValue)

with the explicit Item name (I have only one thermovalve for testing purposes)

Studio_ZWaveThermoValve_ThermostatMode.sendCommand(setValue)

everything works

2020-03-20 23:50:32.291 [INFO ] [ome.model.script.Setting Thermovalve] - Studio_Window_StudWinESP8266reed_DoorSensor has triggered the event!
2020-03-20 23:50:32.302 [INFO ] [ome.model.script.Setting Thermovalve] - Studio has just close! Setting Studio_ZWaveThermoValve_ThermostatMode to 1
2020-03-20 23:50:32.336 [ome.event.ItemCommandEvent] - Item 'Studio_ZWaveThermoValve_ThermostatMode' received command 1
2020-03-20 23:50:32.340 [nt.ItemStatePredictedEvent] - Studio_ZWaveThermoValve_ThermostatMode predicted to become 1

Could you help me with this? And generally, where is there any comprehensive doc (other than this) to understand how to write rules? I have past experience in more “conventional” programming languages (C, C++, Python), is Jython perhaps a valid alternative?

Thanks!
Max

[rossko57]

Your variable thermoValveName is just a string. It happens to look like one your Item’s names, but is just string, same as “banana”. So it doesn’t have a .sendCommand method, it’s not an actual Item.

You are in luck though, the sendCommand() action actually wants to be given an Item name as a string, and will search for it for you.
Beware, the command must be a string too.

sendCommand(thermoValveName, setValue.toString)

For more advanced get-an-Item-from-string-name methods, see

[Rules DSL] Get item from string name!

For a couple years now, I’ve been wanting/looking for a way to construct an item from its name as a string. There are other ways to do this, and the most popular requires the item to be in a group, which can have it’s challenges. I’ll keep this short and SWEET… I finally figured it out, and it is extremely simple! For OH 2.x, you’ll need this import… import org.eclipse.smarthome.model.script.ScriptServiceUtil For OH 3.x, this import instead… import org.openhab.core.model.script.ScriptService…

The general approach you are using is covered here

Design Pattern: Associated Items

Please see Design Pattern: What is a Design Pattern and How Do I Use Them for how to read and use DPs. Problem Statement Often one will have a number of separate Items which are all related to each other in some way. For example, one might have a Contact on a door and a DateTime to represent when the last time the door was opened. This is easy enough to keep track of if there are only one or two such Items, but if one has a lot of similar Items or is using a lot of generically coded rules where…

which includes more than one approach to grabbing an Item by name

[Max77 (Max)]

Thanks @rossko57!

Using the ScriptServiceUtil is nice and works (whole rule below), but reading the comment about resources I will perhaps implement the associated item solution, with the FindFirst function (surely another post will appear here around )

import org.eclipse.smarthome.model.script.ScriptServiceUtil

rule "A door sensor has been triggered"
when
     Member of gOpenItems changed
then
     val String ruleIdentifier = "Setting Thermovalve"
     
     val window = triggeringItem
     
     logInfo(ruleIdentifier, "{} has triggered the event!", window.name)

     val roomName = window.name.split("_").get(0)

     val thermoValveName = roomName+"_ZWaveThermoValve_ThermostatMode"

     var thermoValveItem

     if (ScriptServiceUtil.getItemRegistry.getItem(thermoValveName) == newArrayList) {
          logInfo(ruleIdentifier, "{} does not have an associated thermovalve with name {}", roomName, thermoValveName)
          return;
     }
     else
          thermoValveItem = ScriptServiceUtil.getItemRegistry.getItem(thermoValveName)

     val windowState = if(window.state == ON) "open" else "close"
     val setValue = if(window.state == ON) 0 else 1

     logInfo(ruleIdentifier, "{} got to status {}! Setting {} to {}", roomName, windowState, thermoValveName, setValue)

     thermoValveItem.sendCommand(setValue)

end