Help with time delay that can be canceled

Setup, Configuration and Use Scripts & Rules
3

I find a simpler pattern is;

var Timer doorTimer = null

rule "Notify on door open"
when
    Item Door_Contact changed
then
    if (doorTimer != null)
        doorTimer.cancel()

    if (Door_Contact.state == OPEN) {
        doorTimer = createTimer(now.plusMinutes(5)) [|
             // do notification
        ]
    }
end

This works well since you only need a single rule. When the door is opened, the timer is created. If the door is closed before the timeout then the timer is cancelled. Otherwise the timer fires and you get notified.

Simple but effective.