Working With Combined Fragments

The UML 2.0 Combined Fragment convention lets you define expressions of interaction fragments in any Sequence diagram by assigning an interaction operator and a corresponding interaction operand. Put simply, combined fragments let you define special conditions and subprocesses for any section of any lifeline in any Sequence diagram by specifying (on the diagram itself) an area where the conditions or subprocesses apply.

To create a combined fragment, you define the location of the fragment on your diagram, and then specify a UML 2.0 operator and one or more operands to create the conditions that apply to the target area.

The IDE offers a menu of Interaction Operators. For each condition you assign to an operator, you must supply the operand code to complete each fragment.

In a Sequence diagram window, a newly created combined fragment is represented as a box with an operator tab in its upper left corner. You can specify the operator that appears in the operator tab by right-clicking within the tab. You can also specify an operand expression for the remainder of the box, and add additional interaction operand boxes to a combined fragment to signify additional conditions applied to the initial operator.

The IDE also lets you nest Sequence diagrams. When you nest one Sequence diagram within another Sequence diagram, the nested diagram is represented as a combined fragment displaying the operator ref.

The following topics describe the options you have to work with combined fragments:


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