OH - Rule convert string to float

Items:
String OU_Sensoren_Current_String { http="<[http://192.168.60.142/a?f=j:10000:JSONPATH($.pwr)]" }
Number OU_Sensoren_Current "Stromverbrauch Aktuell [%,.0f Watt]" <energy> (OU_Sensoren)

Rules:
rule "String to float"
when
    Item OU_Sensoren_Current_String received update**
then
    var Number count
    count = Float::parseFloat(OU_Sensoren_Current_String.state.replace(’,’,’.’))
    OU_Sensoren_Current.postUpdate(count)
end