Energy rules, sum of group to item help

[rlkoshak (Rich Koshak)]

@Danonym1

What I want to do is fairly simple. Add all kWh values from the GEnergyLight group to the EnergyLight Item. The reason I want to this is so I can persist EnergyLigth and use it in the rules. As far as I understand Group items like GEnergyLight can’t be persisted and therefore the SUM in GEnergyLight is only useful in the actual sitemap?

You can also use the GEnergyLight’s sum value in your rules. But you are correct, you must persist it for charts. But you are in luck! According to the wiki, if you list a Group in your persistence file the same as you list an Item its sum value will be persisted as well. It is only if you use the “*” after the name that it only persists the members of the group and not the Group’s value. The usual warning about persisting with a once a minute strategy to chart with rrd4j applies.

@Danonym1

So is there and easy way of doing this with group instead of listing all the items in GEnergyLight and combining them?

Not too difficult.

    var Number sum = 0;
    for(NumberItem n : GEnergyLight.members as List<NumberItem>){
        sum = sum + n.state as DecimalType
    }

But like I said above, you don’t need to.

@Danonym1

I’m basically wonderig if this is possible using the .member and a for Each combination instead of listing all the items in the rule.

A normal for loop like above works. The problem with forEach is that you can’t pass it any variables that can be changed so there is no way to get the sum out of the forEach lambda. Use forEach when you want to do something to each Item in the list. Use a for loop like the above if you want to aggregate values.

But again, you can persist the Group directly so the whole conversation about for verses forEach at this point is strictly informative.