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Guideline (Beginner,Concept) Use 'ISA' and 'Is part of' Association links only between actors of the same type.

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Discussion: Role, Agent, and Position are autonomous social actors of different types, which characterize different levels of abstraction. This means that a Role, for example, can be part of another Role, but cannot be part of an Agent or Position. This is true also for Agent and Position. As explained in Guideline 4.1.4, a Role, however, can be associated with an Agent or Position using the Plays and Covers Association Links respectively. An Agent can be associated with a Position using the Occupies Association Link. Refer to Section 4.1 “Actors” and Section 4.2 “Actor Association Links” for definitions of various types of actors and association links.

Figure 1 depicts correct scenarios, which are true also for Agent, and Position. Figure 2 depicts incurrent or wrong scenarios that involve Roles, Agents, and Positions. Figure 3 depict scenarios that are allowed in incomplete (in progress) models as the available information to the modeler about the type (Role, Agent, or Position) of the general ‘Actor’ is not yet known. Once the information becomes available, the correct actor type should be used.


Figure 1   Correct scenarios of using Association Links


Figure 2   Incorrect scenarios that involve Roles, Agents, and Positions


Figure 3   Scenarios that are allowed in incomplete (in progress) models

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Created by system. Last Modification: Tuesday 19 of July, 2011 07:36:42 GMT-0000 by admin.