AND trigger condition

Setup, Configuration and Use Scripts & Rules
1

Hi,

I am trying to create a rule when if I have a virtual switch turned on that a set of actions will be perform every minute but if I turn off the switch then they will not.

It is globally disabling my presence detection.

rule "time to test"
when
    Time cron "0 * * * * ?" and
	Item presence.state == ON
then
    logInfo("location.rule","Execute Location Service Script")
	var String IphoneExec = executeCommandLine("sudo /opt/LocSrvcs.sh", 5000)
	logInfo("presence.rule","Var1 = " + IphoneExec)
end

Can some please advise the correct way to achieve my goal.
Thanks

Paul

2

Using AND is not possible at all, you need to put your presense.state into an if clause:

3

As I am trying to use state and Time conditions it is quite possible for the two to exist at the same time in the real world, as a state is being set for an indeterminable length of time and the time cron fires every minute.

An example of the if statement may well be useful here as I am struggling to see how I combine state item with a time cron in an IF syntax.

Thanks

Paul

4

The real world and two events statement threw me.

However after looking at the other thread and the complete concept even if I disagree with the statement the approach provided makes sense and works.

For anyone else interested this is what my rule looks like

rule "time to test"
when
    Time cron "0 * * * * ?"
then
    if (presence.state == ON) {
	logInfo("location.rule","Execute Location Service Script")
	var String phoneExec = executeCommandLine("sudo /opt/LocSrvcs.sh", 5000)
	logInfo("presence.rule","Var1 = " + phoneExec)
	}
end
1 Like
5

I disagree with the “real world” statement too although it doesn’t apply to this specific question. Events occur simultaneously (to relativistic observers) in the “real world” all the time. I assume when people are are making this claim they mean that openHAB rule engine can’t detect simultaneous events. Even if it could, it would probably not be very useful.

The “when” keyword is part of the problem. If it were named something like “triggers”, it would be less confusing. I’m not sure, but I think the NG rule engine in OH2 uses that terminology instead. One could also argue that if would be better if the “when” part of a rule could contain both triggers and conditions that constrain the triggering (like your original rule). The “then” part would then be more focussed on triggered actions rather than also being responsible for constraining the triggering behavior.

Ideally the triggers would not only be primitive event triggers, but advanced, derived ones. For example, a complex event trigger could be defined as something like the standard deviation of the exponential moving average of a sliding window of an item’s state crossing a threshold (possibly derived from other item states). Another example (a variation of the “simultaneous event” trigger would be something like if Item A’ state changes (or doesn’t change) with 5 seconds of a change to Item B’s state then execute the action. There are certainly ways to work around not having having support for these kinds of triggers (with timers, periodic helper rules, etc.), but I believe it would be less error prone and more useful to nonprogrammers if they were supported in the rule language.

1 Like
6

Don’t quote me on this, but I believe the NG Rules Engine does indeed support conditions. There was another thread that mentioned that right now AND is the only supported boolean operator for triggers in NG rules triggers.

7

It does. It supports them as reusable “modules”. One can also program conditions in a scripted action (or in a JSR223 rule).

You mean conditions, right? I think the triggers are still effectively an OR and the conditions (at least generic conditions) appear to only support AND (although I haven’t seen that confirmed by @Kai).

8

I don’t really know what I mean, honestly. I’ve zero experience with the new rules engine so I may have not followed that thread as closely a I should have.

9

I can confirm :slight_smile:
In short, rules are constructed and executed like this:

10

Paul, rules are ‘fired’ when something happens (changes or is updated) [trigger] on the eventbus (when-part of the rule). In the rule body you can check for current states of items, variable
 by using ‘if’ clauses or ‘case’
 (Check for conditions).

So find your trigger and then check for conditions.

hth

Peter

11

so from left to Right

Trigger, Condition, Action

Is that correct?

Thanks

Paul

12

Yes.