Interaction overview diagram

Interaction Overview Diagram is one of the fourteen types of diagrams of the Unified Modeling Language (UML), which can picture a control flow with nodes that can contain interaction diagrams.^[1]

The interaction overview diagram is similar to the activity diagram both visualizing a sequence of activities. The difference is that the individual activity in the interaction overview diagram is pictured as a frame, which can contain interaction - or sequence diagrams. These interaction/sequence diagrams are constructed with building blocks like: sequence, communication, interaction overview and timing diagram. The nodes in the diagram connect these sequence diagrams, which can be place in a specific order. With these elements the interaction overview diagram can be used to "deconstruct a complex scenario that would otherwise require multiple if-then-else paths to be illustrated as a single sequence diagram".^[2]

Except for the activity nodes the other notation elements for interaction overview diagrams are the same as for activity diagrams, such as initial, final, decision, merge, fork and join nodes. The two new elements in the interaction overview diagrams are the "interaction occurrences" and "interaction elements".^[3]