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14.3.14 InteractionConstraint




    Constraint (from Kernel ) on page 57


Issue 8509 -capitalize ‘boolean’

   An InteractionConstraint is a Boolean expression that guards an operand in a CombinedFragment . InteractionConstraint is a specialization of Constraint.

   Furthermore the InteractionConstraint contains two expressions designating the minimum and maximum number of times a loop CombinedFragment should execute.



   [1] The dynamic variables that take part in the constraint must be owned by the ConnectableElement corresponding to the covered Lifeline .

   [2] The constraint may contain references to global data or write-once data.

   [3] Minint/maxint can only be present if the InteractionConstraint is associated with the operand of a loop CombinedFragment .

   [4] If minint is specified, then the expression must evaluate to a non-negative integer.

   [5] If maxint is specified, then the expression must evaluate to a positive integer.

   [6] If maxint is specified, then minint must be specified and the evaluation of maxint must be >= the evaluation of minint.


   InteractionConstraint s are always used in connection with CombinedFragment s, see CombinedFragment (from Fragments ) on page 487.


   An InteractionConstraint is shown in square brackets covering the lifeline where the first event occurrence will occur, positioned above that event, in the containing Interaction or InteractionOperand .

   <interactionconstraint> ::= [‘[‘ (<Boolean-expression’ | ‘else‘) ‘]’]

   When the InteractionConstraint is omitted, true is assumed.

Issue 7988 -Add second figure to reference.

   Please refer to an example of InteractionConstraint s in Figure 14.11 on page 492 and Figure 14.28 on page 539.