This question is a follow-up to Representing multiple actions for sequence of objects on activity diagram, but isn't strictly related. The question boils down to:
How to present in UML patterns that behave differently depending on how network of handlers is configured.
In simplest case I have the following:
<cfg>
<handler id="1" />
<handler id="2" />
</cfg>
This means that during execution data will be passed first to handler-1 and then to handler-2. But configuration can be changed so that flow is handler-2 and then handler-1, or even handler-2, handler-1, handler-1, handler-2.
And what if handlers can be composed/combined? I can easily create class diagrams for such shenanigans, but activity or sequence diagrams are completely beyond me.