DateTime Conversion (openHAB 3.x)

Tutorials & Examples
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12

#4 Get Java Time from DateTimeType
Tested in OH3, works fine:
val MyJavaTimeFromDateTimeItem = (MyDateTimeItem.state as DateTimeType).getZonedDateTime()

3 Likes
13

Hello,

I had in OH 2.5 the following rule - that calculates my power consuption for one day:

rule “Strom Verbrauch Tag”
when
tem homematic_stecker_Energiezaehler_kwh received update
then
if(homematic_stecker_Energiezaehler_kwh.state instanceof Number){
Stromzaehler_Verbrauch_Tag.postUpdate(homematic_stecker_Energiezaehler_kwh.deltaSince(now.withTimeAtStartOfDay, “influxdb”) as Number)
}

Unfortunately i am not a programmer. Could someone please give me a hint on how to recreate the rule for OH3?

Thanks

KR
Michael

14
2 Likes
15

thanks - now it works

I replaced

now.withTimeAtStartOfDay

with

ZonedDateTime.now().with(LocalTime.MIDNIGHT)

2 Likes
16

Hello,
I didn’t understand Java at all.
I need to convert

now.getWeekOfWeekyear

in oh3 format because now one rule dont work properly.

Many thanks

17

Hi,

When rewriting my rules for OH3, I encountered a problem with the conversion between DateTimeType and Java Time: for some reason, when I convert Java Time to String, the name of my timezone is added to the string, e.g. 2021-01-01T07:00+01:00[Europe/Amsterdam]. This probably has to do with the time zone configuration of the Java environment. Obviously, this leads to problems when the string is parsed.

I also had a problem the other way around. When a DateTimeType was converted to a String, the string was missing a : in the time zone identifier:

DateTimeType to String: "2021-01-01T07:00:00.000+0100"
Java Time expects:      "2021-01-01T07:00:00.000+01:00"

I was able to solve both issues by using a formatter:

  val formatter = java.time.format.DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSZ")

  val morning_start = ZonedDateTime.now().with(LocalTime.MIDNIGHT).plusHours(7) // 7:00

  // Java time to DateTimeType:
  vMorning_Time.postUpdate(DateTimeType.valueOf(morning_start.format(formatter))) 

  // DateTimeType to Java time:
  val day_start = ZonedDateTime.parse(vSunrise_Time.state.toString, formatter)

I hope this helps someone. I’d think this method is more robust in all cases, so it might be recommended to do this, even if you don’t encounter problems yet.

5 Likes
18

You can use the .toLocaleDateTime method to get the time with the time zone. Then you don’t the formatter.
See:
https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/ZonedDateTime.html#toLocalDateTime()
And
https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/LocalDateTime.html

19

#7

now.toInstant.toEpochMilli

now.toEpochSecond * 1000
1 Like
20

#6

val zdt = Instant.ofEpochMilli(XXX).atZone(ZoneId.systemDefault())

val zdt = ZonedDateTime.ofInstant(Instant.ofEpochMilli(XXX), ZoneId.systemDefault())
1 Like
21

#2

val zdt = Instant.ofEpochMilli(XXX).atZone(ZoneId.systemDefault())
val MyDateTimeType = new DateTimeType(zdt)
1 Like
22

hey there

I’m having trouble to figure out the right syntax in OH3 for this:

if (now.isAfter((Sunset_Time.state as DateTimeType).zonedDateTime.toInstant.toEpochMilli) || now.isBefore((Sunrise_Time.state as DateTimeType).zonedDateTime.toInstant.toEpochMilli)

Any hint? thank you very much

23

Sorry for asking, but I don’t get any further allthough reading this over and ober again…
Can somebody give me a code example how to store the time (now) in a variable, and then later calculate the difference in seconds to that stored value??
Thanks,
Ingo

2 Likes
24

Something like this (?):
Post current time to item
My_Item.postUpdate(new DateTimeType())

Get Epoch from Item:
val Number item_millis = (My_Item.state as DateTimeType).zonedDateTime.toInstant.toEpochMilli

Get Now Epoch:
val Number now_millis = now.toInstant.toEpochMilli

Difference in Minutes:
var Number diff = (now_millis - item_millis)/60000

3 Likes
25

@dakoeli: This works for my setup very well! This is exactly what I needed in order to sum up my “uptime firing unit” for calculation of my energy consumption!

Thank you very much!

26

Thanks a lot!!!

27

I still don’t get it to work. I have made a TestRule which I trigger by Hand:

//val DateTimeType Epoche = now.toInstant()
val DateTimeType Epoche = now.toInstant()
logInfo("TestTrigger", "Epoche 2: " + Epoche)


createTimer(now.plusSeconds(3 )) [|
    val DateTimeType Spaeter = now.toInstant()
logInfo("TestTrigger", "Spaeter 4: " + Spaeter)
    val DateTimeType Differenz = Duration.between (Spaeter, Epoche)
logInfo("TestTrigger", "Differenz 5: " + Differenz)

// Here I need to convert from "DateTimeType" to a kind of Number. I want the time Difference in Millisecond or seconds......
	]

This is working so far. I can calculate timedifferences between 2 given times. I get as result:

Differenz 5: PT-3.003164S

which is fine. Now I need this as Number, e.g. “3000” .
So how can the DateTimeType be converted to a Number???

Thanks again,
Ingo

28

I would try the following

val Number millis_spaeter = Spaeter.getZonedDateTime.toInstant.toEpochMilli
val Number millis_epoche = Epoche.getZonedDateTime.toInstant.toEpochMilli

For rule internal internal calculations I would recommend to stay with the Java 11 classes like “ZonedDateTime” or “LocalDateTime”. The DateTimeType I would only use if I want to populate an Openhab Item with it.

(from the javadoc DateTimeType (openHAB Core 3.1.0-SNAPSHOT API))

29

@ljsquare You are right, thanks. I looked up the code of DateTimeType , and it turns out it’s only a thin wrapper around ZonedDateTime. So there is an easy conversion between the two, without the need for any String parsing or formatting.

I’ve rewritten my rule as follows:

  val morning_start = ZonedDateTime.now().with(LocalTime.MIDNIGHT).plusHours(7) // 7:00

  // Java time to DateTimeType:
  vMorning_Time.postUpdate(new DateTimeType(morning_start)) 

  // DateTimeType to Java time:
  val day_start = (vSunrise_Time.state as DateTimeType).getZonedDateTime()

Much cleaner and less error prone.

30

@anfaenger May I suggest to rewrite section #3 of your start post, as follows?

#3 Get DateTimeType from Java Time

DateTimeType has a conventient constructor method that accepts Java java.time.LocalDateTime objects. So getting a DateTimeType if you have a java.time.LocalDateTime is as easy as:

val LocalDateTime myLocalDateTime = new LocalDateTime();
val DateTimeType myDateTimeType = new DateTimeType(myLocalDateTime);
4 Likes
31

Sorry for “hijacking” that chat, but I do not come any further.
My Rules for measuring “working times per day” don’t work under OH3 any more. (And I spent a Day now not getting them to work)
I have A switch which can be On or Off. I need to store the time when the switch goes high, and when it went back to low again. Then subtrated it and transfered the result to an Integer (Seconds).
Seconds = MakeSeconds(TimeNow - TimeBefore)

Maybe you can tell me how to do that OH3 conform?
Thanks in advance,
Ingo