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Object interaction modeling overview
Object Interaction Modeling demonstrates the dynamic behavior that occurs between objects by integrating the static Class Model with use cases.
The Class Model defines the internal structure of objects but says nothing about how they inter-operate whereas use cases depict the operations between objects in the problem domain without concern for the internal composition of the objects themselves.
You can model different aspects of the system domain, reflecting system needs from different user perspectives by depicting the interaction and messaging between objects in the system. Collectively these views and their underlying definitions are referred to as the Object Interaction Model.
The integration of use cases and Class Diagrams in the development of Sequence Diagrams is an iterative process during which the Use Case Model (the users view) and the Class Model (the developers view) is cross checked with user requirements and refined.
Object Interaction Modeling in Modeler involves two types of modeling diagram derived from the Class Model and use cases:
Sequence Diagram—used to describe a use case or an operation in terms of the constructs of sequence, selection and iteration; the passage of time is depicted by an invisible time axis running downward through the diagram
Communication Diagram—used to describe a scenario or path within a use case; comprising objects and message flows between objects, in a snapshot of a time-lapse interaction; each path through the structured language of a Sequence Diagram can be modeled by its own Communication Diagram; typically only the most important scenarios are modeled with Communication Diagrams.
A Sequence Diagram will map directly to one use case. A typical use case will consist of a set of scenarios, or paths, through the system being modeled representing different options within the use case. Each execution path can be represented by a unique Communication Diagram. Therefore several Communication Diagrams can map to one Sequence Diagram.
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