Community Research and Development Information Service - CORDIS

Live sequence charts adapted to UML and real-time

Live sequence charts (LSCs) is a powerful extension of the classical message sequence charts, allowing specification of behavioural requirements for complex reactive systems in a rigorous yet intuitive manner, using a visual language. This result deals with extending LSCs and adapting them for use in an object-oriented UML-based approach, mainly to deal with time and with symbolic-instances.

The time extensions allow a scenario to refer to time and to react to it. A discrete clock object is introduced which generates 'tick' events, this clock object can be used in assignments (for time-stamping) and in time dependent conditions - allowing specification of complex timed requirements.

The LSC language has also been extended with symbolic instances. A symbolic instance, associated with a class rather than with an object, and parameterised by a variable or other expression, may stand for any object that is an instance of the class. This allows specification of object-oriented systems where objects may be dynamically created and destroyed and the number of objects is apriori unknown. It also allows specifying requirements for objects with dynamically changing relations and is thus not restricted to a static object model.

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