A fragment in a UML sequence diagram can be used as an overlay over a number of messages to specify whether these are a sequence, alternatives, optional, parallel, or a loop. There are a few more kinds of fragments specified in the UML standard that can also be used.
An operator is used to indicate the fragment kind, and it is shown in the upper left corner of the fragment. The default fragment kind is sequence (seq).
Example of fragments with different operators
- In the diagram, click the border of the fragment, and then click the
- In the selection window, select the desired operator, and click OK.