In sequence diagrams, you create a combined fragment to represent a construct, such as optional, alternative, parallel, and loop. You group the messages and interaction fragments involved in the interaction in a combined fragment to compact and simplify complex interactions. Interaction fragments refer to the event occurrences, execution occurrences, interaction occurrences, and combined fragments in sequence diagrams.
You can create, move, and resize a combined fragment. When you delete a combined fragment or any of its operands, all messages and interaction fragments that are contained in the combined fragment are deleted from the model.
Creating combined fragments
In sequence diagrams, you create a combined fragment to represent a construct, such as alternative, loop, optional, parallel and so on, in an interaction. Each type of combined fragment is defined by its operator.Moving interaction fragments
In sequence diagrams, you can move the position and change the order of an interaction fragment, which includes combined fragments and interaction occurrences.Resizing interaction fragments
In sequence diagrams, you can horizontally resize any interaction fragment, and you can vertically resize a combined fragment.Adding and removing covered lifelines in interaction fragments
In sequence diagrams, you can add and remove lifelines that are covered by an interaction fragment, which includes combined fragments and interaction occurrences. When you remove a covered lifeline in a combined fragment, all messages and interaction fragments that were contained in the combined fragment and were covered by the lifeline are also deleted.Adding interaction operands to combined fragments
In sequence diagrams, an interaction operand is a container that groups interaction fragments. Interaction fragments refer to the event occurrences, execution occurrences, interaction occurrences, and combined fragments in sequence diagrams. You can add and modify interaction operands in a combined fragment.
Parent topic: Modeling interactions by using sequence diagrams
Related concepts
Sequence diagrams
Interaction frames
Combined fragments