how to represent "sub-sequences" in uml sequence diagrams?
uml
Solution
This can be achieved by using a `<<ref>>` fragment in your sequence diagram, that references a sub sequence diagram.
See for example this picture : http://www.ibm.com/developerworks/rational/library/content/RationalEdge/feb04/3101_figure11.jpg where Balance Lookup and Debit Account are references to other sequence diageams that may in turn contain plenty of lifelines and calls.
Problem
In activity diagrams, you can have a top level activity diagram that contains a sub-activity diagram. This is useful where the sub-activity contains lots of details that you don't want to show in the top level activity diagram. Is a similar concept available for sequence diagrams? Basically, I have a sequence diagram where I want to hide some of the details in the diagram by moving those details to another sequence diagram.