Operations

Scope

Operations are to activities what features are to objects : they are formal descriptions of conditions and consequences that may be performed by different types of objects within different types of activities.

Operations describe conditions and consequences (Mauricio Cattelan)

Operations and Activities

As features, operations are pure descriptions and cannot be instantiated except through activities or objects.  Since the call of operations is meant to trigger activities, their semantics may have some consequence upon system architectures. From that point of view, action semantics must be characterized depending on their scope and contingency:

  • External I/O are local operations, whose execution modify the status of symbolic representations vis-à-vis context counterparts.
  • Computations are local operations whose execution doesn’t modify the status of symbolic representations vis-à-vis context counterparts.

    Local operations: symbolic vs actual changes.

  • Transactions are symbolic operations performed globally, whose execution modifies the status of symbolic representations vis-à-vis context counterparts.
  • Searches are symbolic operations performed globally whose execution execution doesn’t modify the status of symbolic representations vis-à-vis context counterparts.

System operations: transactions modify representations status, searches are neutral.

Operation Semantics

Like features, operations have no meaning on their own but they receive it from execution contexts. At business level, operations can be performed by objects or activities, at system level, assuming an Object Oriented approach, operations are meant to be executed by objects, persistent or transient. In any case the same operation can be interpreted differently depending on context.

In other words, and providing dependencies are properly documented, the architectural impact of operations can be dealt with at object level and, as a consequence, their update can bypass the architecture level of model transformation.

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