Understanding Queues and Context is tricky. If you stick to some rules, mappings can be simplified to great extent. Below video has mapping logic for a common scenario.

Rules:-
– Put filter logic on Node elements.
– Map Leaf elements one – to – one.

Avoid:-
– Avoid removeContexts, collapseContexts, mapWithDefault on Node elements.
– Avoid context change of Leaf elements.

Do’s:-
– Control the occurrence of Node elements by controlling the context of input element.
– Use mapWithDefault for Leaf elements, if required.