Note that the openHAB Item interface has a method called getState. Jython automatically allows calling get/set methods as a Jython property (item.state instead of item.getState()).
Also look at the specific state types, like DecimalType, to find the methods that can be called on instances of them.
Remember, in many cases, Jython is just calling the openHAB/SmartHome Java objects directly.
I did not need the .state however, the members of items already are DecimalType, so this works fine:
alarm_hour = items['alarm_hour'].intValue()
the documentation on jython is frankly pretty scattered around, maybe I will write a small tutorial as soon as I feel to have understood it enough.
Anyway, thank you