State Transition Diagrams

This is a working paper which will probably be rewritten several times in the next months

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AUTHOREN: Leo Pos und Thore Swindall
COLLABORATOR: Dr. Gerd Döben-Henisch
FIRST DATE: December 27, 1995
DATE of LAST CHANGE: March-28, 1996

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A state transition diagram (STD} is related to the description of a single object and all the events of the environment of this object, which have some impact on the object, as well as all responses of the object to these events.

We assume that every event can be seen as a call of a certain method of the object in question. Calling a method implies the activation of this method, this means a method will be processed. Thus every event causes the processing of a method. The 'processing of a method' constitutes a certain state. Every process can generate results which can be understood as responses of the state (= method) to the triggering event. A response terminates a state.

The construction of a STD means therefor the following:

• Identify events
• Identify the processes corresponding to these events
• Identify the specific results (responses) of the processes caused by the events
• Analyze the precedence-structure of all processes: which process presupposes another process or which process follows another process or which processes can be in parallel

Such an analysis can occasionally reveal, that some identified processes are themselves a new object, which have a certain set of methods as their interface to the superordinate object.

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Comments are welcomed to kip-ml@inm.de

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