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14.3.5 Continuation

Fragments


*Generalizations

   

    InteractionFragment (from BasicInteractions , Fragments ) on page 505

*Description

   A Continuation is a syntactic way to define continuations of different branches of an Alternative CombinedFragment . Continuation is intuitively similar to labels representing intermediate points in a flow of control.

Attributes

Constraints

setting : Boolean True when the Continuation is at the end of the enclosing InteractionFragment and False when it is in the beginning.

   [1] Continuation s with the same name may only cover the same set of Lifeline s (within one Classifier).

   [2] Continuation s are always global in the enclosing InteractionFragment (e.g., it always covers all Lifeline s covered by the enclosing InteractionFragment ).

   [3] Continuation s always occur as the very first InteractionFragment or the very last InteractionFragment of the enclosing InteractionFragment .

   Semantics

   Continuation s have semantics only in connection with Alternative CombinedFragment s and (weak) sequencing.

   If an InteractionOperand of an Alternative CombinedFragment ends in a Continuation with name (say) X, only InteractionFragments starting with the Continuation X (or no continuation at all) can be appended.

   Notation

   Continuation s are shown with the same symbol as States, but they may cover more than one Lifeline .

   Continuation s may also appear on flowlines of Interaction Overview Diagrams.

Issue 8326 -fix grammar

   A continuation that is alone in an InteractionFragment are considered to be at the end of the enclosing InteractionFragment .

Figure 14.12 - Continuation

   Continuation (setting==False) Continuation (setting==True)

   The two diagrams in Figure 14.12 are together equivalent to the diagram in Figure 14.13.

Figure 14.13 - Continuation interpretation