Strange error on UpdateSince

1

I get a strange error when trying to access the changedSince method of an item.

My item is defined as follows

Switch gardenlightswitch "Garten-Licht [%s]" <light> (licht, reportEveryChange) ["Switchable"]

My rules implements

logInfo("test","outcome2: " + gardenlightswitch.changedSince(now.minusMinutes(2)))

And the error thrown:

Could not invoke method: org.eclipse.smarthome.model.persistence.extensions.PersistenceExtensions.changedSince(org.eclipse.smarthome.core.items.Item,org.joda.time.base.AbstractInstant) on instance: null

last update works as in the following statement

logInfo("test","outcome1: " + gardenlightswitch.lastUpdate)

So the item is correctly persisted. Any idea?

2

A strange error indeed.

Errors like this usually point to a type error, but I don’t see how that can be the case here, unless it’s trying to convert everything to a String too early. It should return a boolean but I don’t know if it returns a Boolean (primitive versus class with a .toString method). What happens if you add .toString to the call?

3

not much difference

An error occurred during the script execution: Could not invoke method: org.eclipse.smarthome.model.persistence.extensions.PersistenceExtensions.changedSince(org.eclipse.smarthome.core.items.Item,org.joda.time.base.AbstractInstant,java.lang.String) on instance: null

and it doesn’t work in an if clause, that’s why I put it in a LogInfo to see more…

4

My only suggestion at this point is to put the persistence binding you after using into trace log mode and see if it tells you anything interesting.

5

hmm, where di you put .toString? The error message looks odd.

Anyway, if it returns a primitive with no .toString it’ll fail.
Maybe try

if ( gardenlightswitch.changedSince(now.minusMinutes(2)) ) {
   logInfo("test". "changedSince true")
} else {
   logInfo("test". "changedSince false")
}

Which persistence db do you use?

6

Unfortunately it throws the same error on instance:null. That if (true) check was my first intention only to find the root course I wanted to show it in the logs using toString. I use influxDB and mapdb for persistence.

7

If your default persistence is mapdb … changedSince makes no sense with mapdb and its single value storage mechanism.

I think you need to use the extra parameter to changed since to select the service

.changedSince(now.minusMinutes(2),“influxdb”)

Make sure you have a sensible strategy for the Item for a sensible return.