In Unified Modeling Language (UML) sequence diagrams, combined fragments define conditional structures in interactions.
A combined fragment defines an expression of interaction fragments. A combined fragment is defined by an interaction operator and its corresponding interaction operands. You can use combined fragments to describe several traces in a compact and concise manner.
A combined fragment consists of an interaction operator, one or more interaction operands, and an optional guard condition.
As the following figure illustrates, a combined fragment is displayed as a frame that covers lifelines and contains interaction operands. A combined fragment separates the contained interaction operands with a dashed horizontal line between each operand.
Parent topic: Sequence diagrams and diagram elements
Related concepts
Sequence diagrams
Interaction frames
Lifelines
Messages
Execution occurrences
Interaction occurrences
Interaction operators
Interaction operands
Guard conditions
Stop nodes
Related tasks
Developing combined fragments
Resizing interaction fragments
Creating combined fragments
Adding lifelines to combined fragments
Removing covered lifelines from combined fragments