Calculate the difference between 1st january 00:00 actual year and now

Setup, Configuration and Use Scripts & Rules
1

hi !

how can i caclulate the difference in persitent data beween the absulute beginnin of the year and the actual time&date ? im usian actual release on ubuntu

Ciao Gerd

2

Depends on which rule language you use.

In javascript you could get the difference like this:

var yearStart = time.toZDT('00:00:00').withMonth(1).withDayOfMonth(1);
var diff = items.YourItemName.persistence.deltaSince(yearStart);

With this you get the PersistedState object, as you can see in doc here JavaScript Scripting - Automation | openHAB

From PersistedState you can get value as string, number or Quantity:

diff.state(); // as string (with unit, if the item has one)
diff.numericState(); // numeric state (in Item's unit, if the item has one)
diff.quantityState(); // Quantity object allowing you to convert and compare between different units
3

Hi !
I use java but somehow my rule doesnt work

rule “Save yearly consumption em3”
when
Item SP3em_consum changed
or
Time cron “0 0 0 * * ?” //
then
var yearStart = time.toZDT(‘00:00:00’).withMonth(1).withDayOfMonth(1);
var diff = items.SP3em_consum.persistence.deltaSince(yearStart);
SP3em_con_actual_year.sendCommand(diff)
end

and openhab log puts out a lot of errormessages
like
2025-02-19 15:56:15.395 [ERROR] [.handler.AbstractScriptModuleHandler] - Script execution of rule with UID ‘shelly.3em-5’ failed: The name ‘time’ cannot be resolved to an item or type; line 86, column 21, length 4 in shelly.3em

the related items are configured as numbers

Ciao Gerd

4

That’s not Java but Rules DSL, though Rules DSL does use Java classes here and there.

And that’s not code fences. Please use

```
code goes here
```

None of that will work in Rules DSL. You’ll have to use Rules DSL syntax and Rules DSL and Java classes in a Rules DSL rule. You can’t just paste JS into some other programming language and expect it to work.

rule “Save yearly consumption em3”
when
    Item SP3em_consum changed
    or
    Time cron “0 0 0 * * ?” //
then
    // see https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/time/ZonedDateTime.html
    var yearStart =  now.withMonth(1).withDay(1).withHour(0).withMinute(0).withSecond(0).withNano(0)
    // see https://www.openhab.org/docs/configuration/persistence.html#persistence-extensions-in-scripts-and-rules
    var diff = SP3em_consum.deltaSince(yearStart)
    // should be postUpdate, see https://www.openhab.org/docs/configuration/rules-dsl.html#manipulating-item-states
    SP3em_con_actual_year.postUpdate(diff)
end
5

OK Clear so far , but still a failure in log

2025-02-19 23:02:37.073 [ERROR] [.handler.AbstractScriptModuleHandler] - Script execution of rule with UID ‘shelly.3em-5’ failed: ‘withDay’ is not a member of ‘java.time.ZonedDateTime’; line 87, column 23, length 27 in shelly.3em

Ciao Gerd

6

Try withDayOfMonth(1)

7

Hi !

Ok this works… persistence was missing

var diff = SP3em_consum.deltaSince(yearStart,“rrd4j”)

Ciao Gerd